Chapter XVII: Part 17

(2) _Direct examination of the tumor._--In the application of this diagnosis the trained observer will note color, size, shape, and surface structure, transmission of light, movableness, consistence, resistance, pulsation, and crepitation. Percussion, auscultation, and exploration are also available methods. Finally, microscopic examination of the growing portions of the tumor by a pathologist will be found most satisfactory.

GENERAL TREATMENT OF TUMORS.

For benign tumors treatment is required only when it damages the animal's value or when merely for sake of appearance. When it is possible, the removal of the tumor by an operation is indicated. If the tumor has a small, constricted base, remove by torsion, ligation, or with an Ècraseur. Ligation following the incision of the skin with a knife avoids the pain of pressing on the sensitive nerves of the skin and is suitable for tumors of broad base and small bodies. A firing iron, such as is used in line or feather firing, may also be used in removing tumors with small attachments. This not only stops the bleeding but forms a firm scab, under which healing may occur rapidly. Those tumors that can not be removed by the above methods may be treated with caustics or acids, such as sulphuric acid, hydrochloric acid, caustic potash, arsenic, silver nitrate, or chromic acid, but it is difficult to limit the action of these drugs. The injection, into the tumor, of such chemicals as anilin dyes, alcohol, acetic acid, citric acid, or ergotin, is of doubtful value, as is also the injection of the germs of erysipelas--thought by some to be a specific. Certain specific tumors, such as actinomycosis and botryomycosis, may be successfully treated by the internal administration of potassium iodid, together with the injection into the tumor or the painting of its surface with either Lugol's solution or the tincture of iodin. The most reliable means of treating tumors is by extirpation with cutting instruments. Dissect the tumor from the surrounding tissue, ligating all the larger blood vessels, and tearing the tissues with the fingers rather than cutting with a knife. The bleeding may be stopped with a hot iron. The after treatment is the same as for any ordinary wound of similar size.

DESCRIPTION OF INDIVIDUAL TUMORS.

Although a full list of the tumors that may be found in bovines has been given above, there are a number that warrant a detailed description, and the following mention will be made of the most important of them:

MYOMA.

These tumors are after the type of muscle. They are sharply circumscribed and, as a rule, are very hard, a condition owing usually to combination with fibroma and are then known as fibromyoma. In fact, the clinical differentiation between myoma and fibroma is almost impossible. Myomas are found in the uterus, vagina, stomach, intestines, gullet, and bladder of a bovine animal. They grow very large, but, as a rule, are benign. Treatment should consist of their removal.

NEUROFIBROMA.

A true neuroma built up of nerve fibers and nerve cells is infrequent, if it ever occurs, in cattle. False neuromas, or neurofibromas, are knotty, spreading tumors of the size of a large potato, which are developed within the nerve sheaths and composed of nerve fibers and connective tissue bands interlaced. The commingling of these varied fibers is often so intricate that separation is practically impossible. This tumor is most frequently found upon the shoulder of cattle. Treatment is surgical.

ANGIOMA.

The angiomas are tumors composed mainly of blood vessels or blood spaces and are observed on the skin of man, where they are called "birthmarks" or "mother marks." Cavernous angiomas are seen in cattle, affecting the liver and the mucous membrane of the nasal septum. In the liver they appear as smooth, flat, nonprojecting tumors of a dark-red or purple color and of about the size of a silver 10-cent piece. They are somewhat softer in consistency than the adjoining liver substance into which they are gradually fused. These tumors are frequently observed by meat inspectors in livers of slaughtered cattle. Treatment of angioma is unnecessary.

ADENOMA.

The structure of this tumor is after the type of gland tissue. It is rarely seen in cattle except in combination with cancer or sarcoma. A growth which occurs more frequently in bovines, especially calves, and which in some instances bears a striking resemblance to an adenoma is the so-called goiter.

GOITER (STRUMA).

This is a noninflammatory enlargement or a hyperplasia of the thyroid gland. While it can not be definitely classed among tumors, yet, owing to its resemblance to the latter, it will be discussed at this time. The cause of goiter has never been definitely ascertained. Among the most probable causes may be mentioned heredity, insufficient and improper diet, close confinement, unhygienic surroundings, and an unknown toxic substance which is supposed to obtain in those localities rich in magnesium and lime salts. Certain organisms found in goiter have been suspected of producing this trouble, but their relation to the disease has not been satisfactorily proved. A goiter may consist of (1) simple enlargement of the follicles which are filled with albuminous matter (follicular goiter); (2) an increase of connective tissues between the follicles, causing the swelling to be dense and resistant (fibrous goiter); (3) a great increase in size of one or more follicles, forming a cyst (cystic goiter); (4) great dilatation of the blood vessels in the gland accompanied with pulsation with each heart beat (vascular goiter).

_Symptoms._--Goiter may be observed at the side of the throat, reaching the size of a fist or even larger, or it may hang down below the windpipe. In cattle the two thyroid glands are close together, and when the disease affects both there may be but one uniform swelling placed in front of the windpipe below the angle of the jaw. This swelling may be hard, soft, or doughy in consistence, and with each beat of the heart it may pulsate like an artery. It may cause labored breathing by pressure on the windpipe, and death may result from pressure on this structure, on the gullet, or on the adjoining large vessels.

_Treatment._--In young animals the treatment is usually satisfactory, and consists in giving the animal a complete change of feed and plenty of exercise in the open air. If the condition appears enzootic in the district, remove the animal to another location when possible. Iodin, either in the form of ointment or the tincture, should be applied to the swelling. Injections of iodin solution, 5 grains of iodin in 1 dram of 25 per cent alcohol, may also be made into the substance of the gland. When the swelling which follows this injection has subsided it may be repeated. Potassium iodid should be given internally in 1-1/2 dram doses twice daily for a cow, or in 20-grain doses twice a day for a calf. Extirpation of all but a small section of the swelling may be successfully accomplished by a qualified veterinarian, but if it should be entirely removed, myxedema and death follow.

FIBROMA.

Fibromas are tumors made up chiefly of connective tissue and are usually confined to the skin and subcutaneous tissue. Indurative fibromas of the skin appear as tumors of gelatinous connective tissue or as firm, white vascular connective tissue growths, which are more or less sharply outlined, move readily over the underlying tissues in company with the skin, and owe their origin to mechanical injuries, perforating wounds, repeated abrasions, or the invasion of pus cocci or botryomyces into the tissues.

These tumors in cattle are frequently found upon the dewlap as solid lumps, hard as stone to the touch, lying loosely between the layers of skin, and gradually losing themselves in the softer tissues of the neck above, or as smooth, hard tumors of glistening white substance with interlacing lines of softer tissue. They may also be found in the region of the knee or at the elbow. The skin over the growths, in accordance with the originating cause, will be found chafed, covered with scabs, or even ulcerated and accompanied with collateral edema.

These connective tissue tumors grow slowly but reach enormous size. They sometimes follow injuries to the region of the throat and form there as hard, firm growth, even reaching the size of a child's head.

A fibroma upon the larynx is not an infrequent occurrence in the ox. These tumors are always sharply outlined and have a roughened surface. They may be differentiated from actinomycotic tumors (see chapter on "Infectious diseases of cattle," p. 358) in the same location by their firm, fibrous structure and by the absence of pus from the interior.

A tumor is sometimes seen upon the muzzle of cattle, which assumes a diameter equaling the width of the muzzle. It is a voluminous connective-tissue formation known by the name of "fibroma diffusum."

Another form is sometimes observed upon the tongue. It grows upon a broad, spreading base, becoming very hard. It is almost lacking in blood vessels, although the few that are present are plainly in view, and in consequence is poorly supplied with fluids. It is of a smooth contour, white or whitish yellow in color, is sharply limited from the normal substance of the tongue, may be covered with mucous membrane, on which prominent papillÊ are located, or only by a thin, delicate layer of epithelium, and is usually found in the middle part of the tongue, where it may reach the size of two fists.

Pedunculate or stemmed fibrous tumors are frequently noticed growing upon or near the extremity of the tails of cows. They are apparently of traumatic origin, such as tying the tail fast while milking or shaving it too closely while trimming for show purposes, and usually contain bloody or gelatinous material within, or, again, they may be strongly edematous throughout.

_Treatment._--The treatment of large fibromas is surgical and consists of the operative removal of the tumor, followed by suturing of the wound. Small external tumors may be painted with zinc chlorid, chromic acid, or a concentrated solution of bichlorid of mercury.

PAPILLOMA (WART).

When fibromas develop from the lining or covering tissues they frequently form papillary growths, more or less thickly covered with epithelium, and are then called papillomas, or warts.

Papillomas consist of villouslike projections, resulting from a proliferation of the outer layer (epithelium) of the skin or mucous membrane. These growths are also called "angle berries," and may assume a variety of forms. Sometimes there is a preponderance of epidermis in the formation, and the tumor then appears as a hard, dense, insensitive, clublike growth, or wart. Again the swelling is chiefly in the derm, or true skin, and we have what is known as a flesh wart (verucca carnea). In other cases the growth of papillar bodies projects in great cauliflowerlike tumors with deeply furrowed and lobulated surface, over which a covering of epidermis may or may not be present. These are usually much softer and are well supplied with blood vessels. It is not uncommon for them to be pedunculate or stemmed, and in this case considerable rotary motion or twisting is possible. Their color is cloudy gray or grayish red, with white bands of connective tissue radiating from the center. Their consistence varies. Upon their surfaces and within their clefts and fissures they undergo retrogressive changes, softening, bleeding, or ulcerations.

A favorite location for the papilloma in cattle is the udder and teats, where they may develop in such numbers as to cover the entire surface and make the animal troublesome to milk. The sides of the head, neck, and shoulders also afford satisfactory conditions for their growth, and are frequently seen to be affected by them.

_Treatment._--Warts may be removed with the scissors, twisted off with the fingers, or ligatured by means of a rubber band or horsehair. The roots should then be cauterized with tincture of iron, glacial acetic acid, or lunar caustic. Acids should never be used in removing warts about the eyes or in the mouth. Papillomas of the eyelids sometimes change to cancers and should be removed by taking out a wedge-shaped section of the eyelid. Young cattle should be given arsenic internally in the form of Fowler's solution, 1 tablespoonful twice a day for a 6-months-old calf.

POLYPS.

Polyps are usually fibromas or myxomas, occurring on the mucous membrane of the nasal passages or genital tract. They grow upon a narrow stem, bleed readily when injured, and often contain a center of thin, limpid fluid. A bloody discharge is sometimes seen coming from the affected nostril, but this is not always easy of detection in cattle, owing to the pliancy of their tongues and to their habit of licking an irritated nostril. Usually these tumors grow downward and may project from the nostril, causing snoring sounds and uneasy breathing. They may occasionally force themselves backward into the throat, where they interfere seriously with respiration, the patient being obliged to breathe with an effort, and even forced to cough in order to dislodge temporarily the obstruction from the larynx. Such tumors, when near the nostril, may easily be removed by the use of forceps or a loop made of bailing wire. Serious bleeding is not liable to follow their removal, but an astringent wash, such as a solution of the perchlorid of iron, if applied to the cut surface, will be found very beneficial. In case the tumor is not within easy reach, the services of a qualified veterinarian should be obtained to perform the necessary operation.

LIPOMA.

This is a tumor consisting chiefly of fat cells. The growth is irregularly rounded and distinctly lobulated, very soft, and almost fluctuating. It is insensitive, grows slowly, and is always inclosed in a distinct fibrous capsule, from which it can be easily shelled out. It may become very large and often hangs pendulous from a long, elastic pedicle. In cattle this tumor may be found in the subcutaneous tissues, especially of the back and shoulders, uterus, and intestines, and in the latter position it may cause strangulation, or "gut tie," by winding around a loop of the intestine.

_Treatment._--When found on the skin the tumor may be readily removed with a knife or by a ligature. Caustics and the cautery produce wounds that heal slowly and can not be recommended in the treatment of this tumor.

CHONDROMA.

This tumor formation is composed of cartilage cells. It is a rounded and very often unevenly nodular and sharply described tumor. It is very hard, dense, elastic, and painless and develops principally where we find normal cartilage cells. It is rare in cattle, but has been found in the subcutaneous tissues and nasal cavities.

_Treatment._--Extirpation.

OSTEOMA (BONY TUMOR).

Bones may occasionally grow in such a profuse and irregular manner that the product, or osteophyte, assumes the character of a tumor. The bone tissue may possess either spongy or compact properties and grow either from the periphery of the bone or within its interior. These tumors most frequently appear about the head of the animal, either upon the jawbones, within the nasal passages, or in connection with the horns. They are usually of bony hardness, painless, benign, and sharply outlined.

_Treatment._--The treatment consists in either removing them with a saw, chisel, or trephine, or preventing their further development by counterirritation with blisters or firing iron.

MYXOMA.

Characteristic myxomas are mucoid tumors which chiefly originate from the mucous membrane and are especially to be found within the nasal passages and uteri of cattle. They can reach a size of three fists, are smooth or velvetlike, or may be lobulated, broad at the base, and consist of a glassy-looking mass of connective tissue, which usually shows a distinctive yellowish color. Being homogeneous and elastic, the moist, jellylike tissue composing the tumor may be easily destroyed or crushed. When cut through, these tumors soon collapse from the loss of their fluids. They sometimes inclose elliptical cavities filled with slimy, gelatinous masses.

_Treatment._--Extirpation.

SARCOMA.

This is a malignant tumor after the type of embryonal tissue, and consists of several varieties, such as the round cell, spindle cell, giant cell, alveolar, and melanosarcoma. They grow by preference in connective tissue and are quite vascular. Sarcomas appear either as single or multiple nodules, varying in size from a hempseed to a hazelnut, or else as a moderate number of tumors of the size of hen eggs. Their surface, at first smooth, later becomes lumpy and tuberous from internal degeneration. Secondary nodules may appear near the primary tumor. The outer skin is not involved so soon as in cancer, nor does ulceration follow so rapidly. Sarcoma is about the most frequent and dangerous tumor that is found in cattle. It occurs in young animals, and is found on the serous membranes, in the glandular organs, and on the outer skin, especially of the neck and shoulders--in fact, in nearly every tissue and in almost every part of the body. This tumor is often found in places exposed to traumatisms and at seats of scars, or of irritations from pressure and inflammation.

_Treatment._--Treatment should consist in early and complete removal by the knife, including one-half or three-quarters of an inch of the sound tissue adjoining the tumor. If there is a possibility that sarcomatous tissue still remains, either cauterize the wound with a hot iron or powder the walls of the cavity with arsenious acid.

CANCER (CARCINOMA).

Cancers are tumors of epithelial tissues and are malignant. There are several varieties of cancers, such as hard, soft, and colloid, but only those growing on the surface will be mentioned here. These malignant tumors of the superficial organs develop primarily from the epidermis or from the glands of the skin. They appear secondarily as spreading infections from milk glands, thyroids, anal glands, or as embolisms. In such cases their sole character depends wholly upon the kind of cancer from which they have sprung. The infiltrating cancer begins as an elevation of the skin, which progresses until it becomes rough and nodular. The surface later becomes attacked, and an ulcer results whose edges are outlined by a hard, firm zone.

The ulcerations may remain limited by cicatricial tissue, but it is more likely that the infiltration and destruction of tissue will spread out wider and deeper until a rodent ulcer (so called) is formed. One of the most frequent sites of cancer in cattle is in the eye, where they are called fungus hematodes, but they also occur on the skin, on the genitals, in the stomach, and within the organs.

_Fungus hematodes._--This starts at the inner corner of the eye as a papillary elevation or as small nodules which become fused. They grow larger and become papillomatous, with superficial ulcerations and a tendency toward hemorrhage. In some cases the eye is displaced by the growing tumor or is attacked by the cancer cells and entirely destroyed.

Cancerous growths upon the external genitals and the anus usually present a rough, irregular surface from which there is a constant sloughing of decomposed tissue accompanied with a penetrating disagreeable odor.

The diagnosis of cancer may be made clinically by noting the simultaneous infection of the lymph glands which surround the primary lesion. Deeply burrowing and infiltrating forms which appear as lumps and ulcerations cause marked disfiguration of the affected part. The surface becomes a soft, greasy mass; later it cracks open and from the fissures blood-colored pus exudes, being continually formed by the moist degeneration of the tissues beneath. At first the general health of the animal does not appear affected, but later the cancer nodules spread to important organs and give rise to marasmus and progressive emaciation. Cancer is not a frequent tumor of cows. Frˆhner states that of 75 cases of tumors in cattle which came under his observation 2, or 2.6 per cent, were found to be cancers, while 20, or 26.6 per cent, were sarcomas.

_Treatment._--Treatment consists in the early and complete removal of the tumor, taking care to include a wide border of healthy tissue. This has been most successful in such superficial cancers as those of the eye, penis, anus, testicle, vulva, and sheath. If the disease has advanced too far, this treatment may not prove efficacious, owing to the great malignancy of the cancer and its tendency to recur. In such cases the animal may be slaughtered, but the flesh should be used for food only after inspection by a competent veterinarian.

CYSTS.

Cysts may be true or false tumors and consist of a capsule containing a fluid or semisolid content. Among the most important cysts, which have been briefly referred to in a previous table, the following are probably the most noteworthy, owing to the frequency with which they are found in bovines:

SOFTENING CYSTS.

Softening cysts, which result from the degenerative liquefaction of normal or diseased tissues, especially of tumors of different kinds, followed by the encapsulation of the fluid.

PARASITIC CYSTS.

Parasitic or foreign-body cysts, from the inflammatory reaction induced by such parasites as the echinococcus (hydatid cyst) or by the presence of various kinds of foreign bodies.

EXTRAVASATION CYSTS.

Extravasation cysts, caused by injuries which rupture blood vessels, followed by an increase of fibrous tissue which forms a capsule about the fluid. The hygromata in front of the knee in cattle, so-called tumor of the knee, and serous cysts belong to this variety.

HYGROMATA, OR TUMORS OF THE KNEE.--These consist in the simplest form of a collection of serous fluid mixed with fibrin within a distended bursa. The walls surrounding the fluid become firm, smooth, and dense.

Outwardly the tumor appears fluctuating, though tense, while the skin which covers it may be normal, denuded of hair, or covered with hard epidermal scales, possibly half an inch in thickness, forming a hard, horny plate. The cavity which contains the fluid may have the dimensions of a hen's egg, an apple, or a child's head. Its walls are formed by the diseased secreting membrane of the bursal sac, and are readily detachable from the subcutis of the skin. Their internal surfaces are often uneven or supplied with projections or tufted growths which support a fibrous network within the tumor.

Tumors of the knee may also assume a granular type, as the result of chronic inflammation or following operative or spontaneous evacuation of pus from the part. They are either firmly connected with the skin or are detachable from it, and when laid open disclose a whitish-red, porklike tissue surrounding a central nucleus of pus, or a fistulous tract leading to the outer surface. They are caused by the chronic inflammation which follows the bruises received by cattle in lying down and in rising, or they may be due to falls on uneven, hard ground.

_Treatment for hygromata._--When the swelling first appears cold water should be applied, followed later by bandaging with cloths wrung out of warm water. If the swelling is soft, it should be punctured at the lowest point, and afterwards the cavity should be syringed with Lugol's solution. If the tumor is hard and nonfluctuating, a mercurial blister may cause absorption and at the same time prevent further injury to the part by making it more painful, thus sparing it.

SEROUS CYSTS.--These swellings are another variety of extravasation cysts, and are caused by such injuries as butting, running against hard objects, and shipping bruises, which are followed by an outpouring of blood and lymph into the tissue spaces. These cysts develop rapidly and may reach the size of a man's head or even larger. They are soft, edematous, and hot at first and contain a serous or blood-tinged fluid. Later, partially organized clots and shreds of a fibrinous nature and of a gelatinous consistence are formed within, and the temperature of the swelling is reduced. They appear on the surface of the body, especially on the belly and flank of cattle.

_Treatment of serous cysts._--Treatment consists in opening the cyst at the most dependent point with a sharp knife. The cavity should be washed out twice daily with a 5 per cent solution of carbolic acid, and drainage encouraged by keeping the incision open.

DERMOID CYSTS.

These cysts have a wall which is almost an exact duplicate of the structure of the skin, and frequently contain epidermal structures, such as hair and teeth, which, in the development of the embryo, have been misplaced. Thus we may find in an ovary or testicle a dermoid cyst, containing a tooth or a ball of hair. Dental cysts are included in the class above.

DENTAL CYSTS.--It happens occasionally that the teeth of cattle, instead of developing normally within strong supporting alveolÊ, remain inclosed within a cystic membrane, which assumes a tumorlike character. One tooth may be included alone in the cyst or a number may be inclosed together. However this may be, the malformation progresses, especially if confined to the incisor teeth, until the remaining teeth that began to develop normally are crowded out of position and rendered useless. The tumor may reach the size of a man's fist. It appears to be fleshy and dents upon pressure, but it may also appear on closer examination as though it contained irregular sections of thin bone. The outer surface is always smooth, and no indication of purulence, softening, or scab formation is ever exhibited. Upon being laid open with the knife the tumor is seen to be surrounded by a firm, smooth membrane which limits it completely from the adjoining tissues. It is filled with material which possesses partly edematous, partly fleshy, and partly bony properties. It is supposed that this mass is composed of rudiments of the jawbone or of the alveolar walls which, becoming spongy, lose themselves in the soft, fleshy mass contained within the capsule of the tumor. It occasionally happens that the tumor is hollow and that the cavity extends back into the body of the lower jaw for a considerable distance.

Tumors of this kind, being of congenital origin, are very naturally observed most frequently in young cattle, but they may continue to expand for a period of several months after the birth of the calf, even until they become troublesome and unsightly.

_Treatment for dental cysts._--Treatment consists in the complete extirpation of the cyst and the destruction of the lining pouch by curetting.

RETENTION CYSTS.

Retention cysts arise from the retention of normal secretions, owing to obstruction of a duct leading from a gland. The mucous cysts found in the mouth, udder, and vestibule of cows are samples of this form.

MUCOUS CYSTS.--Saclike dependent tumors, caused by retention of the secretions from the mucous glands, sometimes develop in the mouth, nose, pharynx, and vulva of cattle. They are called "mucous cysts." These are of sizes varying from peas to pigeon eggs, are roundish and translucent, and surrounded by a delicate, vascular membrane. They contain a siruplike substance more or less thick and transparent and whitish yellow in color.

Treatment consists in the puncturing of the swelling, if accessible, and the destruction of the cyst walls by the injection of Lugol's solution.

PROLIFERATION CYSTS.

These are found especially in the ovaries of cows, called "cystic ovaries," and may produce nymphomania (chronic bulling).

The treatment indicated in this case is the removal of the diseased ovaries.

FOOTNOTES:

[3] The term "tumor" literally means a swelling, and thus has been applied to the prominence caused by an overdistended bladder, to the enlargement of pregnancy, to the swelling produced by an abscess, to the overgrowth of tissue (hyperplasia) associated with injury and consequent inflammation, and to numerous other phases of tissue enlargement directly connected with recognized disease processes. For this reason it is becoming more common for scientists to apply the word "neoplasm" to the new growths described in this chapter. Because of the still popular use of the word "tumor," it is retained in this chapter for the designation of those new growths to which the sevenfold characterization of our descriptive definition applies.

DISEASES OF THE SKIN.

By M. R. TRUMBOWER, D. V. S.

[Revised by John R. Mohler, V. M. D.]

GENERAL DISCUSSION.

The skin consists of two parts--a superficial layer, the epidermis, or cuticle, and the deep, or true, skin, the dermis, cutis vera, or corium.

The epidermis, cuticle, or scarf skin, is an epithelial structure, forming a protective covering to the corium. It varies in thickness, is quite insensible and nonvascular, and consists of a sheet of cells.

The epidermis is divided into a firm and transparent superficial and a deep, soft layer. The latter is the rete mucosum, whose cells contain the pigment which gives color to the skin. The deep surface of the epidermis is accurately molded on the papillary layer of the true skin, and, when removed by maceration, presents depressions which correspond to the elevations on the dermis. From the cuticle tubular prolongations pass into the sebaceous and sudorific glands; thus the entire surface of the body is inclosed by the cuticle.

The dermis, or true skin, is vascular and highly sensitive, containing the tactile ends of the nerves of touch. It is covered by epidermis and attached to the underlying parts by a layer of areolar tissue, which usually contains fat. The cutis consists of a fibro-areolar tissue and vessels of supply. It is divided into two layers, the deep, or true, corium and the upper, or papillary. The corium consists of strong interlacing fibrous bands, chiefly white; its meshes are larger and more open toward the attached surface, giving lodgment to the sweat glands and fat. The papillary, or superficial, layer is formed of a series of small conical eminences or papillÊ, which are highly sensitive, and consists of a homogenous, transparent tissue. The blood vessels form dense capillary plexuses in the corium, terminating by loops in the papillÊ. The papillary nerves run in a waving manner, usually terminating in loops.

Hair is an appendage of the skin and forms its external covering. It is a special modification of epidermis, having the same essential structure, and consists of a root, shaft, and point. The root has a bulbous extremity, is lighter and softer than the stem, and is lodged in a recess or hair follicle, which may either be in the corium or subcutaneous areolÊ. The follicle is dilated at the bottom to correspond to the root bulb, and the ducts of one or more sebaceous glands open into it. At the bottom of each follicle is a conical, vascular papilla, similar in every respect to those on the surface of the dermis; this papilla fits into a corresponding depression in the root of the hair. The shaft consists of a center, or medulla, a surrounding fibrous portion, and an external coating, or cortex. The medulla consists of cells containing pigment or fat, is opaque, and deeply colored. All kinds of hair do not have this medulla. The fibrous portion occupies the bulk of the stem, and the cortex is merely a single layer of thin, flat, imbricated (shinglelike) scales.

The sebaceous glands, lodged in the corium, are most abundant in parts exposed to friction. They generally open into the hair follicles, occasionally on the surface of the body. Each gland consists of a small duct which terminates in a lobulated recess. These lobules vary, and are, as is the duct, lined with epithelium. They are filled with sebaceous matter which, as it is secreted, is detached into the sacs. They are very plentiful between the claws of cattle.

The sudorific glands, or sweat glands, are situated in the subcutaneous areolar tissue, surrounded by a quantity of fat. They are small, round, reddish bodies, each of which consists of one or more fine tubes coiled into a ball, the free end of the tube being continued up through the true skin and cuticle, and opening on the surface. Each sweat gland is supplied with a cluster of capillary blood vessels which vary in size, being very large when perspiration is excessive. The contents of the smaller ones are fluid, and of the larger, semifluid.

The skin may be regarded as an organ supplementary in its action to the lungs and kidneys, since by its secretion it is capable of removing a considerable quantity of water from the blood; it also removes small quantities of carbon dioxid, salts, and in certain instances during suppression of the renal secretions a small quantity of urea. The skin is also the chief organ for the regulation of animal heat, by or through conduction, radiation, and evaporation of water, permitting of loss of heat, while it also, through other mechanisms, is able to regulate the heat lost. The hair furnishes protection against extreme and sudden variations of temperature by reason of the fact that hairs are poor conductors of heat, and inclose between them a still layer of air, itself a nonconductor. The hairs are also furnished with an apparatus by which the loss of heat may be regulated; thus, in cold weather, through the contraction of unstriped muscular fibers of the skin, the hairs become erect and the external coat becomes thicker. Cold, too, acts as a stimulus to the growth of hair, and we find, in consequence, a thicker coat in winter than in summer. The hairs also furnish protection against wet, as they are always more or less oily from the secretion of sebaceous glands, and thus shed water. Through their elasticity they furnish mechanical protection, and through the thickness of the coat, to a certain degree, resist the attacks of insects. Finally, the hairs assist the sense of touch.

The sweat glands are constantly discharging a watery secretion in the form of insensible perspiration, and by their influence act as regulators of the temperature of the body; hence, in warm weather, the secretion of the skin is increased, which tends to prevent overheating. Sweating, in addition to regulating heat, is also an active agent in removing effete material from the blood; therefore this secretion can not be checked without danger. If the skin is covered with an impermeable coating of grease or tar, death results from blood poisoning, owing to the retention of materials destined to be excreted by the skin.

All secretion poured out by the skin is not only modified by the condition of the atmosphere but also by the character and quantity of the food, by the amount of exercise, and especially by the quantity of fluid taken.

The sebaceous secretion is intended to lubricate the skin and hairs. It consists of soft, fatty material suspended in water, and is characterized by an odor peculiar to the animal by which it is secreted.

I will not attempt to classify the various diseases of the skin, for in a work of this kind it would serve only to confuse the reader.

We shall first consider a class of diseases which are of an inflammatory type; next, those caused by faulty secretion and abnormal growth; then, diseases of parasitic origin; lastly, local injuries of the skin.

PRURITIS (ITCHING).

We shall consider pruritis first as a distinct subject. It is not a disease, only a sensation, and therefore a symptom. It is one of the symptoms accompanying the majority of the diseases which we will consider in this chapter. It is, then, a functional affection produced by slight irritation from without or by an internal cause acting upon the sensory nerves of the skin. Nothing characteristic is seen except the secondary lesions, produced mechanically by scratching or rubbing.

There are various forms of itching, the result of specific skin diseases, where the pruritis is a secondary symptom. In such cases it should not be regarded as an independent affection.

_Causes._--Many causes may induce the condition which we recognize here as pruritis. The most common one is dirt on the skin, resulting from insufficient care. If the ceiling of the stable is open, so that dust and straw may fall, the skin is irritated and pruritis results. It also occurs in some forms of indigestion.

The parts of the body most exposed to this condition are the croup, the back, the top of the neck, and the root of the tail.

Another cause is found in affections of the liver and of the kidneys, when an increase of effete material has to be thrown off by the skin. Morbid materials circulating in the blood may produce a tickling or smarting sensation of the skin in their passage from the blood to the free surface of the skin. Certain irritating substances when eaten may be excreted by the skin, and coming thus in direct contact with the sensory nerves produce itching, or may go further and cause distinct inflammation of the skin. In another class of cases the pruritis may be ascribable to an atrophy, contraction, or hardening of the skin, when the nerves become irritated by the pressure. These conditions may be so slightly marked in a thick skin like that of the ox that they can not be recognized. It is frequently noticed that cattle rub themselves as soon as they pass from the stable into the open air--changing from a warm to a cold atmosphere. Again, we may find one that does all its rubbing in the stall. We may look for lice, but fail to find them. These conditions are generally attributable to high feeding and to too close confinement. They may be associated with inflammatory irritation or not; certainly we fail to discover any morbid changes in the skin. There is to some extent a delightful sensation produced by rubbing, and it may partly become a habit of pleasure.

_Treatment._--We must place our chief reliance upon a change of food, plenty of exercise, and in most cases the administration of an active cathartic--1 to 1-1/2 pounds of Epsom salt, a handful of common salt, a tablespoonful of ginger or pepper, mixed with 2 quarts of water, all of which is to be given at one dose. Afterwards half an ounce of hyposulphite of soda mixed with the feed may be given twice a day for a week. For an external application, when the skin is abraded or thickened from rubbing, a solution of borax, 4 ounces to the quart of water, may be used. Carbolic acid, 1/2 ounce to a quart of water, will give relief in some cases.

INFLAMMATORY DISEASES OF THE SKIN.

ERYTHEMA.

This is the simplest form of inflammation of the skin. It consists of an increased redness, which may occur in patches or involve considerable surface. The red coloration disappears when pressed by the finger, but soon returns after the pressure is removed. There is seldom much swelling of the affected part, though often there is a glutinous discharge which dries and mats the hair or forms a thin scale upon the skin. In simple erythema the epidermis alone is affected; when it becomes chronic, fissures form and extend into the corium, or true skin.

_Causes._--Simple erythema, consisting of an inflammatory irritation, is seen in very young calves, in which the navels leak. The discharge being urine, it causes an irritation of the surrounding skin. Chafing, which is another form of erythema, is occasionally seen on the udders of cows from rubbing by the legs; chafing between the legs is not uncommon among fat steers. Chronic erythema is found in the form of chapped teats of cows and chapped lips in sucking calves. It frequently occurs in cows when they are turned out in winter directly after milking, and in others from chafing by the sucking calf. Some cows are peculiarly subject to sore teats. The fissures when neglected in the early stage of formation become deep, very painful, often bleeding at the slightest touch, and when milked in that condition cause the animal to become a kicker. Occasionally the lower portions of the legs become irritated and chapped when cattle are fed in a muddy or wet yard in winter, or if they are compelled to wade through water in frosty weather. Another form of erythema occurs in young cattle highly fed and closely stabled for a long winter. The erythema appears in patches, and as it is most common near the end of the winter it is known as the "spring eruption" or "spring itch."

_Treatment._--In ordinary cases of erythema the removal of the cause and the application of benzoated oxid of zinc ointment, carbolized cosmoline, or ichthyol ointment applied a few times, will restore the skin to a healthy condition.

When there are fissures the zinc ointment is the best. If at the teats, a milk siphon (Pl. XXIV, fig. 4) should be used instead of milking by hand, and the calf, if one is suckled, should be taken away. The calf should be fed by hand if its mouth is affected. When the legs are irritated or chapped, dry stabling for a few days and the application of tar ointment will soon heal them.

URTICARIA (NETTLE RASH, OR SURFEIT).

This is a mild, inflammatory affection of the skin, characterized by sudden development of patches of various sizes, from that of a nickel to one as large as the hand. The patches of raised skin are marked by an abrupt border and are irregular in form. All the swelling may disappear in a few hours, or it may go away in one place and reappear on another part of the body. It is always accompanied with a great desire to rub the affected part. In its simplest type, as just described, it is never followed by any serous exudation or eruptions, unless the surface of the skin becomes abraded from scratching or rubbing.

_Causes._--Digestive derangements caused by overloading the stomach when the animal is turned out to graze in the spring, certain feed constituents, high feeding of fattening stock, functional derangement of the kidneys, spinal and other nervous affections, are the most common sources of nettle rash.

The disease consists in paralysis of the nerve ends that control the volume of the capillary vessels in certain areas of skin, thus permitting the vessels to expand, their contents in part to exude, and thus produce a soft, circumscribed swelling.

_Treatment._--Administer a full dose of Epsom salt. Give soft, easily digested feed, and wash the affected parts with a solution of bicarbonate of soda (common baking soda), 8 ounces to the gallon of water twice a day, or diluted glycerin may be applied to the skin. If it assumes a persistent tendency, give a tablespoonful of the following powder in the feed three times a day: Cream of tartar, sulphur, and nitrate of potassium, equal parts by weight; mix.

ECZEMA.

Eczema is a noncontagious inflammation of the skin, characterized by any or all of the results of inflammation at once or in succession, such as erythema, vesicles, or pustules, accompanied with more or less infiltration and itching, terminating in a watery discharge, with the formation of crusts or in scaling off. The disease may run an acute course and then disappear, or it may become chronic; therefore two varieties are recognized, vesicular (or pustular) and chronic eczema.

_Causes._--Eczema is not so common among cattle as in horses and in dogs, in which it is the most common of all skin diseases. Among cattle it is occasionally observed under systems of bad hygiene, filthiness, lousiness, overcrowding, overfeeding, excessively damp or too warm stables. It is found to develop now and then in cattle that are fed upon sour substances, distillery swill, house or garden garbage, etc. Localized eczema may be caused by irritant substances applied to the skin--turpentine, ammonia, the essential oils, mustard, Spanish-fly ointment, etc. Occasionally an eruption with vesiculation of the skin has been induced by the excessive use of mercurial preparations for the destruction of lice. It is evident that eczema may arise from local irritation to the skin or from an autointoxication. Cattle fed on the refuse from potato-starch factories develop a most obstinate and widespread eczema, beginning on the legs.

_Symptoms._--In accordance with the variety of symptoms during the progress of the disease we may divide it into different stages or periods: (1) Swelling and increased heat of the skin; the formation of vesicles, which are circumscribed, rounded elevations of the epidermis, varying in size from a pinhead to a split pea, containing a clear, watery fluid; (2) exudation of a watery, glutinous fluid, formation of crusts, and sometimes suppuration, or the formation of vesicles containing pus (pustules); (3) scaling off (desquamation), with redness, and thickening of the skin. From the very beginning of the disease the animal commences to rub the affected parts; hence the various stages may not always be easily recognized, as the rubbing produces more or less abrasion, thus leaving the skin raw-- sometimes bleeding. Neither do these symptoms always occur in regular succession, for in some cases the exudation is most prominent, being very profuse, and serve to spread the disorder over a large surface. In other cases the formation of incrustations, or rawness of the skin, is the most striking feature. The disease may be limited to certain small areas, or it may be diffused over the greater part of the body; the vesicles, or pustules, may be scattered in small clusters, or a large number run together. The chronic form is really only a prolongation of the disease, successive crops of pustules appearing on various portions of the body, frequently invading fresh sections of the skin, while the older surfaces form scabs, or crusts, upon the raw, indurated skin.

In old, standing cases the skin breaks, forming fissures, especially on portions of the body that bend--the neck and limbs. Thus the disease may be prolonged indefinitely. When eczema reaches its latest period, either acute or chronic, desquamation of the affected parts is the most prominent feature. The formation and shedding of these successive crops of scales constitute the character of the disease frequently denominated psoriasis.

_Treatment._--The treatment of eczema is often anything but a pleasant task. There is no one method of treatment which always proves successful, no matter how early it is begun or how small an area is involved. We must endeavor to remove the cause by giving attention to the general health of the animal and to its environment. Feeding should be moderate in quantity and not too stimulating in character--green feed, bran mashes, ground oats, clean hay, plenty of salt. If the animal has been fed too high, give an active purgative--Epsom salt preferred--once a week, if necessary, and half an ounce of acetate or nitrate of potassium may be given in the feed twice a day. If the animal is in poor condition and debilitated, give a tablespoonful of the following mixture in feed twice a day: Powdered copperas, gentian, sulphur, and sassafras bark, equal parts by weight. If the animal is lousy, the parasite must be destroyed before the eczema can be cured. The external treatment must vary with the character of the lesions; no irritating application is to be made while the disease is in its acute vesicular, or pustular, stage, and, in the chronic stage, active stimulants must be used. Much washing is harmful, yet crusts and scales must be removed in order to obtain satisfactory results from the external applications. Both objects, however, can be attained by judiciously combining the curative agents with such substances as will at the same time cleanse the parts.

In the vesicular stage, when the skin is feverish and the epidermis peeling off, thus exposing the exuding dermis, an application of boric-acid solution, 2 drams of the acid to 8 ounces of water, often relieves the smarting or itching, and also serves to check the exudation and dry the surface. If this fails to have the desired effect compound cresol, 1 ounce to 2 quarts of water, should be used as a wash. Either of these washes may be used several times a day until incrustation is well established. Then compound cresol, 1 ounce to 2 quarts of sweet oil, or the benzoated oxid of zinc ointment, giving the affected surfaces a thorough application once a day, will be efficacious. When the eczema is not the result of an external irritant, it takes usually from one to two weeks to heal.

In chronic eczema, when there is a succession of scabs or scales, indolent sores or fissures, the white precipitate ointment, nitrate of mercury ointment, or blue ointment, mixed with equal parts of cosmoline or fresh lard, may be applied every second day, taking care to protect the parts so that the animal can not lick it off.

The internal administration of arsenic often yields excellent results in chronic eczema. Dissolve 1 dram of arsenic and 1 dram of carbonate of potassium in 1 pint of boiling water, and give 1 ounce of this twice a day in water, after feeding. An alkali internally may be of service. As such, one may give 2 ounces of bicarbonate of soda twice daily. Sublimed sulphur may also be tried in ounce doses twice daily.

PUSTULES (IMPETIGO).

Impetigo is an inflammatory disease of the skin, characterized by the formation of distinct pustules, about the size of a pea or a bean, without itching. The pustules develop from the papular layer of the skin, and contain a yellowish-white pus. After reaching maturity they remain stationary for a few days, then they disappear by absorption and dry up into crusts, which later drop off, leaving upon the skin a red spot that soon disappears. Occasionally the crusts remain firmly adherent for a long time, or they may be raised and loosened by the formation of matter underneath. The dry crusts usually have a brown or black appearance.

_Causes._--Impetigo affects sucking calves, in which the disease appears upon the lips, nostrils, and face. It is attributed to some irritant substance contained in the mother's milk. Impetigo is also witnessed among grazing animals, regardless of age, and it especially attacks animals with white hair and skin. The mouth, face, and limbs become covered with pustules, which may rupture in a few hours, followed by rapid and successive incrustations; the scabs frequently coalesce, covering a large surface; pus may form under them, and thus the whole thickness of the skin become involved in the morbid process. This form of the disease is attributed to the local irritant properties of such plants in the pasture as St. John's wort (_Hypericum perforatum_), smartweed (_Polygonum hydropiper_), vetches, honeydew, etc. Buckwheat, at the time the seeds become ripe, is said to have caused it; also bedding with buckwheat straw.

_Treatment._--Sucking calves should be removed from the mother, and a purgative given to the latter to divert the poisonous substance secreted with the milk. When the more formidable disease among grazing cattle appears, the pasturage should be changed and the affected parts of the animal thoroughly anointed once a day with sweet oil containing 2 drams of carbolic acid to the pint. This should be continued until the crusts soften and begin to drop off, then the parts may be cleansed thoroughly with warm water and soap. Subsequently the white precipitate ointment or carbolized cosmoline should be applied daily until the parts are healed.

PEMPHIGUS (WATER BLISTERS).

This is an inflammatory disease of the skin, characterized by successive formations of rounded, irregularly shaped water blisters, varying in size from a pea to a hen's egg.

_Causes._--Obscure.

_Symptoms._--The formation of a blister is preceded by a congestion or swelling of the skin. Yellowish-colored water collects beneath the cuticle, which raises the latter from its bed in the form of a blister. The blisters appear in a succession of crops; as soon as one crop disappears another forms. They usually occur in clusters, each one being distinct, or they may coalesce. Each crop usually runs its course in a week. The disease is attended with itching or burning sensations which cause the animal to rub, thereby frequently producing excoriations and formation of crust on the affected region.

_Treatment._--Give a tablespoonful of the following-described mixture in feed twice a day: Saltpeter, cream of tartar, and sulphur, equal parts by weight. The blisters should be opened as soon as formed, to allow the escape of the serum, followed by a wash composed of chlorid of zinc, 1 dram to 15 ounces of water. When there is any formation of crusts, carbolized cosmoline should be applied.

FURUNCULUS (BOILS).

This is an acute affection of the skin, usually involving its whole thickness, characterized by the formation of one or more abscesses, originating generally in a sebaceous gland, sweat gland, or hair follicle. They usually terminate by absorption, or by the formation of a central core, which sloughs out, leaving a deep, round cavity that soon heals.

_Causes._--Impoverished state of blood, the result of kidney diseases or of local friction or contusions, with the entrance of pus cocci through the damaged skin or through a hair follicle or a sebaceous gland.

_Symptoms._--Boils in cattle usually appear singly, not in clusters; they may attain the size of a hen's egg. The abscess begins as a small round nodule, painful on pressure, gradually increases in size until death of the central portion takes place, then the surface of the skin gives way to internal pressure and the core is released and expelled. Constitutional symptoms are generally absent, unless the boils occur in considerable numbers, or by their size involve a great deal of tissue.