Chapter C: F. Dawson, in investigating a wasting disease of well fed Brahma (5)

Active grooming and even the stimulating effect of cold douches may be invoked, the skin being rubbed actively until dry and warm.

If the circulation is poor, a stimulating steam or hot water bath of fifteen minutes followed by a cold sponge and rubbing till dry may be profitably substituted. In such cases it is well to put a cold sponge on the head while in the bath.

Medicated inhalation is often valuable especially when the lesions are on, or near the bronchial mucosa. In 1868, Dewar met with most successful results from inhalation of sulphurous acid gas impregnating the atmosphere as strongly as the patient can breath without discomfort. His own groom who had given up work because of advanced phthisis, under treatment of half an hour three times a day, became ruddy, gained weight, and betook himself to work again. In rabbits which I inoculated with human sputa, the same year, all died tuberculous excepting one which I fumigated three times a day for weeks. This rabbit remained plump and well.

As an example of a still more irritating inhalant, I watched the case of a phthisical man who secured employment on the government disinfecting corps, in Chicago, in purifying the lung-plague-infected stables with chloride of lime solution, and who very soon began to improve, gaining weight and strength, his cough meanwhile subsiding.

Cervello’s use of formalina by inhalation though well spoken of by its inventor would seem too irritating on the delicate lungs, however good it is as an antiseptic.

Inhalants may be conjoined with the pneumatic cabinet.

Among agents used to moderate the cough may be named codeine, morphia, cherry laurel water, wild cherry bark, guaiacol, menthol, syrup of Tolu, or chloroform, or alcohol inhalation.

As an internal antiseptic, carbonate of creosote has often proved beneficial.

Mustard blisters on the skin covering the tubercle is claimed by Knopf to act beneficially by attracting the microbes from the delicate lungs to the more robust skin and connective tissue, where they can be better disposed of by the more abundant leucocytes.

He has also found excellent results in complex infections in animals from the use of Marmorek’s streptococcic serum in doses of 10cc., followed after the second dose by 5cc. every 24 hours. In other cases it failed of the effect (reduction to normal temperature) evidently indicating that the hyperthermia was maintained by other microbes than the streptococcus. The principle is good, and perhaps at some time in the future a bacteriological examination of the sputum may reveal the microbes present and suggest the sera for such complications.

The introduction of air into the peritoneum has long been known to exercise a retarding and curative action on abdominal tuberculosis. At the present writing my colleague, V. A. Moore, is experimenting by pumping air and oxygen into the peritoneum and pleuræ in cattle slightly affected, with encouraging results.

I should add that isolated superficial tubercles may often be excised to advantage, and the part dressed antiseptically.

It is only in exceptional cases, however, that one is warranted in preserving and running the danger of spreading the tubercle bacillus for the advantage that can be secured to individual animals from treatment.

EXTINCTION OF TUBERCULOSIS IN CATTLE.

As cattle are the great propagators of tuberculosis on the farm, the question of extinction necessarily centres around this race. As in all other dangerous infections, the most prompt and successful method would be in the time honored one of destroying the infected and thoroughly disinfecting all their products. The only barrier to success in such a case would be the conveyance of infection anew from man to cattle after the herd had been purified. The demonstration that cattle are less susceptible to infection by the human sputa than many had supposed does away largely with this objection, as in a generally purified bovine race, the few primary cases contracted from man could be easily taken care of. Then, if tuberculous persons were interdicted from attendance on cattle, the danger in this direction would become very nearly a negligible quantity.

There remains the question of expense and many honestly consider this as absolutely prohibitory. The estimate of 5 per cent. of our 68,000,000 head to be killed and paid for at $25 per head, would be $85,000,000. But there is no necessity for this. Our fat steers at the packing houses are tuberculous only to the extent of 0.02 per cent., speaking well for their dams and nurses. The estimate of 5 per cent., based upon the testing of those few herds that have been taken because they were already known to be tuberculous, is unquestionably far above the actual ratio for the United States. It may apply to dairy cattle in some infected districts, but, for the bovine race of the whole country, it is absurdly high. If we had 10, 20 or 50 per cent. infected, as in some countries of Europe, the objection of expense might be a formidable one, but when the ratio of the infected is but 2:10000, we have every encouragement on the score of expense to enter on a campaign of extinction. But again, we do not need to deal with 68,000,000 cattle as we can omit the steers which are so little affected and which will all come to the slaughter house in two or three years. The source of their infection (a few cases excepted) is in the older cows and bulls of the dairy and breeding herds, and this brings down our total to a little over 17,000,000. The average census price for dairy cows is $29 and, as the condemned cows are depreciated by their condition, it would be a high average to estimate them at $20. Again, the average infected ratio of cows for the entire country would be set high at 2 per cent., and on this basis it might well be that the required indemnity would not aggregate much over $6,000,000. Five or even ten times that amount would be a mere trifle in comparison with the $3,000,000,000 value, constantly encreasing, of our domestic animals, with the $99,210,272, representing our yearly product of beef and beef products, with our annual dairy products, worth $500,000,000, (Alford), or with our yearly loss of 100,000 of our population in the very prime of life when they are of the greatest value to the country, representing a yearly drain of $100,000,000, beside all the suffering and loss entailed by their prolonged and too often helpless idleness. Though this last item is doomed to continue for a length of time after the disease has been extinguished in our herds, it is receiving constant accessions from the latter, and can never be entirely done away with until our cattle are above suspicion.

An even more serious problem is the demand for tuberculin and above all for accomplished, experienced and honorable veterinarians fitted to conduct the sanitary campaign over the entire country. The tuberculin cannot be produced in a week or a month, yet the problem of its production in any required amount in a few months is merely one of the encrease of existing plants under the management of the same careful hands now engaged upon it. As to veterinarians it would be impossible to secure at once the required staff of men capable of carrying out the work over the whole country. But this is not essential. The work can be begun in the counties supplying the large cities with milk, and in the great butter and cheese producing areas where it is so urgently needed, and it must be made to include all thoroughbred herds, which are so constantly drawn upon to improve the blood elsewhere, and each herd, county and district, as freed from infection must be scheduled and no additions made to it from outside, except under the guarantee of the tuberculin test, repeated in six months. The reacting animals, must be appraised, excluded from the herd, and disposed of, it may be to the butcher to be killed under official expert inspection, and the salvage, if any, to be deducted from the appraised value; or to be rendered and the salvage estimated; or to be buried as the case may be. In all such cases the other animals (horses, pigs) that occupy the same buildings and yards should be tested, although the risk of the infection of cattle from these animals is comparatively small. Unless in badly infected herds, steers and young cattle, which can be kept in a separate herd need not be tested. Vermin must be killed. Thorough disinfection must be applied to buildings and yards, and the dairy herd must be retested at the end of every six months until no more reactions are met with.

In this way the campaign in any State can be begun with a small staff, which may be steadily encreased as men are trained to the work, and in no great length of time the dairying and breeding herds can be purified and the investigation carried into the more purely agricultural fields, where herds are small and usually free from infection. Many minor points would require the attention of a competent superintendent of the work. My object here is to make a plea for the approved and attested method which has never failed in the case of other animal infections on enclosed farms, and which is based on the absolute destruction of every seed of the disease in the area under sanitary control. The method has the apparent drawback, that it demands a greater relative outlay at the start, than do others proposed, but in view of its certainty, and the confident hope of an early abolition of all infection, loss, and expensive expert control, it must, in my opinion, be looked upon here, as it has always proved in the past, the course of the truest economy. It may be compared to the treatment of a field of thistles by removing the offensive weeds, root and branch, before they have advanced to seed, instead of merely cutting them down with a mower, and leaving the roots, to grow anew, to leaf, to blossom and seed, in spite of the temporary partial drawback. But as the prospect of early legislation along this line is not a bright one, the expert must accommodate his aims and efforts to what can be done under the existing laws.

_Breeding Healthy Stock from Parents with Latent Tuberculosis._ When a State is not pledged to exterminate tuberculosis by prompt and radical measures, it is quite possible to raise healthy stock from sires and dams that have the disease in a latent form. It is very exceptional that calves are born tuberculous. If, then, they are kept in a pure environment and furnished with the milk of sound nurses, or even with the milk of their own tuberculous dams, after it has been heated for one-quarter of an hour to 180° F. or 212° F. they can be preserved in perfect health.

This is especially adapted to herds of valuable thoroughbreds, the destruction of which would be a serious loss, and the preservation of the strain of blood a most desirable object.

The whole herd should be tested with tuberculin, and the advanced and generalized cases, that can be detected by objective symptoms, should be at once destroyed and safely disposed of. The animals in good condition and that have not reacted should be placed in a new barn and yard, or where no tubercle has been, or in places that have been thoroughly disinfected, under special attendants. There will remain the animals in good condition with no objective symptom, but that have reacted, and these are placed in separate barn, yard and pasture well away from other stock, under their own attendants, for breeding purposes. They should have the best of food and air, clean, well lighted, roomy buildings with shelter from storms, clean sheltered yards, and in summer, pasturage. Any cow showing indication of active advance or generalization of the disease (cough, wheezing, dyspnœa under exertion, excessive pallor of mucosæ, unthriftiness) should be at once separated and destroyed as endangering the reinfection of others, and the stable subjected to disinfection. The calf, as soon as born, must be removed to a special building or park, where it shall get milk from a sound cow or that of its own dam after it has been carefully sterilized. After sterilization the milk cannot safely be returned to the unscalded pail into which it was drawn from the cow, and it should be fed by separate attendants who have not milked nor handled the affected animal. Any loss of condition, unthriftiness, cough or scouring on the part of any of the calves should be the signal for its separation from its fellows, subjection to the tuberculin test, and, if it reacts, for its destruction and the disinfection of the building where it was. It is well to test each calf at six weeks old and to remove the reacting ones. The success of this method is now well established.

Goodman, of Dorpat, applied it largely as early as 1891, rearing the healthy calves of reacting cows on the milk of cows that had stood the test. Bang, of Denmark, raised such calves to sound maturity on sterilized milk. Reynolds, of Minnesota, reports the raising of twenty-four healthy calves from infected cows on the milk of tested cows, while three fed on milk of reacting cows, which was supposed to be sterilized, all became tuberculous. McEachran (1899) in an extended experiment succeeded perfectly with the milk of tested cows only. I have now in hand a Jersey herd in which the progeny, fed on the milk of their reacting dams, became tuberculous without exception, and in the years following, those fed on the milk of the same reacting cows after it had been kept at 180° F. for half an hour all grew up healthy.

Under this method, inasmuch as the infection is not at once extinguished, but temporized with for the benefit of the stock owner, State indemnities are not necessarily called for. Yet the State can profitably test the cattle at public expense, mark indelibly those that react, schedule them and control them, so that they will not be allowed to change hands nor to mingle with sound animals until finally butchered, dead or recovered. The State should see to the thoroughness of the seclusion, disinfection, the safe disposal of all products from milk to manure, and the testing at intervals of three or six months of both cows and calves.

_Raising Healthy Offspring Without Sterilizing the Milk._ In the northwest territories cows and heifers that have reacted to tuberculin, but which otherwise appear to be in good health, are made into a herd by themselves and placed on a special range apart from all other cattle. They live in the open air, slight shelter being allowed in winter only, and their calves are allowed to suck the dams until winter. The wide range, the open air life, and the early destruction by oxygen and sunshine of the discharged bacilli, tend in the main to ward off infection, except such as comes in the milk, and the majority of the calves grow up in apparent health and are fattened for market. A small minority are born tuberculous or contract the infection from the milk, but this does not seriously impair the financial success, and living in the open air they bring little danger to others. The loss is infinitesimal as compared with the expense of milking a large herd, sterilizing the milk and feeding it by hand. Advanced cases, with objective symptoms, should always be removed, and the cows may be tested at intervals if compatible with profit. The seclusion of the herd should be complete, by distance, by the configuration of the country, or by fence.

For this system the climate of our Southern States, where stock can remain out of doors all the year, offers a better field than the semi-arctic northwest.

_Removal of all Unthrifty Animals and Those Showing Physical Symptoms of Tuberculosis._ Before the days of tuberculin testing I succeeded in extinguishing tuberculosis in several herds by the prompt removal of all unthrifty animals and such as showed objective symptoms of tuberculosis, the disinfection of the buildings, the restocking from sound herds, and the strict separation of the new stock from the old. In one herd of 200 this entailed the final destruction of the whole original herd; in others the destruction was in the main limited to particular (susceptible) families. But in these days, with the tuberculin test available, a resort to a method of this kind would produce an unnecessarily slow, uncertain and expensive result.

_Removal of Animals Showing Objective Symptoms or Reaction under Tuberculin._ The Bang (Danish) method is the chief example of this, and is so considerate of both state outlay and stock owner’s interests that it is deserving of high praise. Under it the State usually waits for the stock owner to take the initiative, but to encourage applications from the owners, it furnishes tuberculin testing without expense, and even allows a small indemnity for animals killed because of advanced tuberculosis. In return for this the stock owner agrees to furnish separate buildings (or enclosures), yards and pasturages, new or, when necessary, disinfected, one set for the high conditioned, nonreacting, healthy herd, and a second for the animals that reacted but which show no further sign of tuberculosis, with separate attendants, utensils and other appointments for each. This reacting herd is furnished with the best of food, air, accommodation and hygiene generally, and the milk is sterilized before it is allowed to pass into consumption by man or for calves or pigs or for the production of butter. The quarantined herd is marked, registered, and kept under government surveillance; it cannot be parted with for stock uses, but it is at the disposal of the owner to keep it for milk, or fatten at once for the butcher. Finally every member of this herd is slaughtered under government inspection, and the beef put on the market or sent to the rendering works as may be decided. The system secures the hearty coöperation of dairyman, dealer and government, and while it comes short of the speed and efficiency of a generally applied method of extinction, it is accomplishing a great work for Denmark, putting an immediate stop to the advance of the disease in the worst infected herds, and placing the latent cases of such herds in a safe seclusion for the rest of their lives. At first the tested herds showed 40 per cent. affected; now less than 20 per cent.

The feature which would be likely to work the least satisfactorily in the United States, is the disposal of the sterilized milk as such. It is to be feared that this milk would find but a poor market with us, and if it proved unsalable, the preservation of the reacting herd would be no longer an economic success.

In Pennsylvania where practically the same method is in force, leaving it in the option of the owner to keep the reacting latent cases and sterilize their milk, or to abandon them to the State, have them appraised and slaughtered with indemnity, the uniform practice has been to accept the latter alternative. Not a single owner, I believe, has elected to keep a herd in quarantine and sell the milk sterilized. The result has been that four times the number of applications come in that the appropriation will warrant the officials to take in hand.

A special feature of the Pennsylvania method is the provision that a stockowner can have his herd examined, and tested with tuberculin, at his expense, the State to furnish a certificate setting forth the condition of the animals. In case of infection, the owner has the option of abandoning the reacting ones to the State, to be secluded, or appraised and slaughtered, he meanwhile guaranteeing that he shall introduce no new animals into the herd except by tuberculin test under the direction of the State Board.

The usual provision is in force that no indemnity is allowed for any animal that entered the state not more than three months before, and without the tuberculin test demanded of all such stock animals.

Indemnities are restricted to $25 per head and under for non-registered animals and grades, and $50 for registered thoroughbreds. The average appraised price has been $23.

On the whole an excellent work is being done in Pennsylvania, and herds now tested are found to contain not more than half as many infected animals as did those tested a few years ago. A better showing would doubtless have been made if the State appropriation had permitted the board to give attention to all applications made.

The good results may be attributed to the adoption of a system which secured the confidence and trust of the stockowner: he sees that the State has no desire to oppress nor injure him; he is in no dread of a high-handed confiscation of his remunerative property without indemnity; while advanced cases are destroyed he is left the option of segregating his latent cases and marketing their products under the precaution of sterilization; he can raise the progeny of these animals if he will, under similar precautions; he can sell his stock and its product under government certificate if they prove sound; he can avail of government assistance in protecting his herd against reinfection, by the testing of animals to be purchased. Under such a system there is no object in secreting infection, and in underhanded sale of tuberculous animals, with the spread of the disease into new centres. Even the tardy or inimical stockowner is roused to action by public opinion, when he finds the market for his suspected product growing more and more uncertain, and feels the daily encreasing pressure of opinion among neighboring owners, that he is exceeding his rights in maintaining an infected herd in the very midst of their purified ones.

A most important item of the system of Pennsylvania, and of sixteen other states, is the compulsory testing of all stock cattle introduced into the State. This has the further support of the Federal Government which demands a tuberculin test of every stock bovine animal imported into the United States. This is a natural corollary of every attempt to restrict or extirpate tuberculosis from a State, but when through willful blindness a great State like New York, repudiates a measure of this kind, it but makes its dairy and breeding herds the depository of the reacting animals that other states wisely exclude. The sifting process goes on at Buffalo and other centres and the New York herds are loaded with the rejected, diseased animals. Under the operation of this, and the denial of indemnity for animals slaughtered, it will be wonderful, if the New York stock owner is not soon roused up from his idle dream of fancied security, by a great extension of the infection.

_Generally Applicable Measures._ Under any system many special rules will be demanded in individual cases, which it will require the skill of the expert sanitarian to apply, and which cannot be referred to here. The following are generally applicable whether by the owner in his particular herd, or by the State or other authority dealing with the subject.

1st. On discovery of a case of tuberculosis, test the whole herd with tuberculin. (See Tuberculin Testing.)

2d. Remove all animals that show a typical reaction.

3d. Destroy and burn, boil or deeply bury all cases of the disease, unless it is decided to form an isolated herd of latent cases which are in good condition and apparent good health.

4th. In case of doubt or disturbing influence which may have caused rise of temperature (calving, heat, exposure, concurrent disease, changes in management, etc.), keep the suspected animal apart for four weeks and test again.

5th. Repeat the test every six months, and if two successive tests show no indication of tuberculosis, the herd may be accounted sound.

6th. As soon as tuberculous animals have been removed from a stable, let it be vacated and thoroughly disinfected with chloride of lime, 4 ozs. to 1 gallon of water, and enough quick lime to make a good whitewash which will show if even a square inch is missed. When chloride of lime is objectionable because of its tainting the milk, use mercuric chloride 1 dr. to 1 gallon water, with enough sal ammoniac to make it freely soluble. The roof, walls, and especially the floor, gutter and feeding trough must be first thoroughly scraped, washed and cleaned, all rotten wood work must be removed, and, in case of double boarded walls, the boards must be removed on one side to permit of a thorough application. Utensils should be scalded and dressed with carbolic acid, 1:20. A stable incapable of disinfection should be abandoned for a length of time or burned.

7th. In making new purchases, avoid any herd in which tuberculosis has appeared, or that has had sickness or deaths in recent years.

8th. Do not purchase from city, suburban nor swill stables.

9th. Do not take a cow that is in ill health or low condition, especially one with cough, nasal discharge, foul breath, wheezing breathing, hard nodules under the skin, diseased udder, swollen bones or joints, or a tendency to scour or bloat.

10th. Test every animal with tuberculin before admitting it into the herd.

11th. Do not admit strange cattle to house, field or yard. Keep apart from the herd until tested.

12th. Keep each animal strictly to its own stall and manger.

13th. Board up between the stalls in front so that no two cows can feed from the same manger.

14th. Be especially watchful of the older cows and on the slightest sign of ill health, separate and subject to the tuberculin test.

15th. In case a herd of cattle is found to be tuberculous, subject to the tuberculin test all domestic animals that have mingled with them freely and fed from the same troughs. Remove those that show a reaction.

16th. Exterminate the vermin (rats, mice, sparrows) in a building where tuberculosis has prevailed.

17th. Let no consumptive person attend on cattle nor prepare their food.

HYGIENE OF MILK AND MEAT. SANITARY POLICE MEASURES.

This has a reference to both man and beast and involves measures of private and public hygiene alike. In man, as we have seen, milk is the source of greatest danger, being habitually taken uncooked, whereas meat has been usually subjected to a high temperature before it comes to the table.

_Milk._ The unsterilized milk of the tuberculous cow must always be regarded with grave suspicion. Especially is the drinking of milk warm from the cow to be strongly condemned. The feeding experiments of Vilemin, Gerlach and others, in 1866 to 1869, demonstrated the virulence on the lower animals of the milk of infected cows, and many accidental infections have shown the same for man. (See relation of the bacillus of man to that of animals). This conceded, the question arose as to the virulence of milk drawn from the sound udders of tuberculous cows. Many experiments of Nocard, Galtier, McFadyean and others seemed to decide against such infection. Others have had a different experience, and especially when the test was made by inoculation. Ernst found tubercle in 30 per cent. of the cows he examined, though no affection of the udder could be made out. Theobald Smith, Hirschberger, Bang and others found tubercle bacilli in milk from sound udders. Pearson, injecting the milk from sound udders intraperitoneally into Guinea pigs had ten in sixty-three affected. Rabinowitsch and Kemper found tubercle bacilli in ten out of fifteen cows with sound udders. While it must be allowed that often a very small proportion of tuberculous cows with sound udders pass the bacilli in the milk yet a sufficient number of exceptions are found to deter one from endorsing such milk as safe. Much more is this conclusion justified by the consideration that commencing mammary tuberculosis is in many cases unrecognizable by ordinary examination intravitam or post mortem. Again when the bacilli are circulating in the blood (generalized tuberculosis) they can escape from such a vascular tissue as the mamma without the formation of a local lesion, as they can pass through the intestinal walls or lungs and colonize the adjacent lymph glands. Nocard’s injections of the bacilli into the veins seem to show that they disappear from the blood in 4 to 6 days, but with a generalization of the infection from within, the presumption is against a single isolated entrance of bacilli, and in favor of a continuous introduction. In such generalization therefore the bacilli circulate in all vascular tissues, and are liable to escape with any normal secretion, but especially with the milk or urine on account of the great vascularity of the glands.

When the udder is itself tuberculous the case is incomparably worse. The milk can scarcely fail to be infecting, and the bacilli, grown in these highly vascular tissues, apart from the air, are usually of a very virulent type. Of these Martin writes in the report of the Royal Commission (England): “The milk of cows with tuberculosis of the udder possesses a virulence which can only be described as extraordinary. All animals inoculated showed tuberculosis in its most rapid form.” Woodhead is equally positive in this position. Galtier says “we should absolutely avoid the consumption of milk from cows in which the udder is tuberculous, and boil before using, the milk of all cows affected with, or suspected of tuberculosis in any form.” Finally we should never consume without boiling, milk of which we do not certainly know the origin, and especially in cities, we ought not to omit this precaution in the case of milk furnished by milkmen.” Rabinowitsch and Kemper add: “Milk from cows that react to tuberculin must be suspected of being tuberculous in every case.”

It may well be allowed that the mixed milk from a large dairy, containing but one or two tuberculous cows, is much less infecting than that of the tubercular cow herself, and that skim milk that has been passed through the separator has been robbed of many bacilli which have been precipitated in the albuminoid material that collects on the inner side of the bowl. But these mean dilution not purification: they reduce the danger but do not altogether remove it, and sanitary police should aim at sterilization in every case where available.

_Butter_, _cheese_, _whey_, and other dairy products have been proved virulent in different cases (Galtier, Heim, Lasar, Bang, Obermüller, Roth, Groëning, Gasperimi, Petri, Rabinowitsch). This was true for butter 120 days old, and cheese 330 days. In a number of cases Rabinowitsch found a bacillus, similar to the tubercle bacillus and producing tubercle-like lesions, but differing in its staining, morphology and culture, and she supposed that other observers had mistaken this for the tubercle bacillus. Petri, Morgenroth and Hormann, found the bacillus of Rabinowitsch in company with the real tubercle bacillus in butter, and Rabinowitsch, later, in fifteen samples of butter found the bacillus tuberculosis in two.

Bacilli coming from the mouth, bowels, or lungs, are also liable to get into the milk, through the floating dust of the stable, or from the teats, udder, tail, etc., (Gaffky).

_Oleomargarine_ cannot be considered as free from this indictment, for though the tuberculous glands, etc., from the mesentery, may be sterilized in the preliminary heating process, yet the subsequent mixing with milk is liable to convey the infection.

The ideal course with milk, if the herds cannot be purified from tuberculosis, would be to compulsorily remove from the herd every cow that shows objective symptoms of tuberculosis, or any internal disease of the udder, and to subject all the milk of the remainder to Pasteurization at a temperature of 155° F. for twenty to thirty minutes. This, however, requires skilled and faithful management to avoid renewed contamination from the lips of the vessel which may have escaped the heat, or from hands, vessels and objects that were in contact with the milk before. The boiling temperature for fifteen minutes would be a safer resort, as requiring less careful handling, yet even this may be contaminated afterward under poor management. It has the further drawback of the boiled milk taste and the coagulation of the albumen. But the outlay for such careful sterilization will soon amount to more than will the tuberculin test.

_Meat._ For various reasons meat must be held less virulent than milk, but mainly because it is less frequently the seat of tubercle than the udder, and because it is usually cooked before being eaten. The muscular tissue of the ox appears to be unfavorable to colonization by the bacillus, and although the intermuscular lymph glands do not partake of this inherent resistance, yet as the glands are very frequently affected from the tissues which they drain, they necessarily partake in some degree of the comparative immunity of the muscles. This immunity is, however, far from complete, as the frequent implication of the intermuscular glands (prescapular, axillary, prefemoral, etc.), sufficiently show. Again in estimating the virulence of meat we must never forget that in the great majority of cases, in ordinary infected herds, the tubercle is still essentially local; no generalization has taken place. The muscle is vascular throughout, and in cases of generalized tuberculosis is infecting, yet a single transient escape of tubercle bacilli into the blood does not ensure permanent infection of that fluid, which can usually purify itself in six days or less (Nocard). On the contrary, when the escape of bacilli into the blood is constant, so becomes of necessity the virulence of the blood and a rapid generalization ensues. Such continuous escape may occur in actively advancing tuberculosis at any point, but it is more certain if the degenerating tubercle has opened through the walls of the vessels (capillaries), so that the infecting bacilli can pass into the blood in a continuous stream. The pus and other microbes, in complex infections, hasten this degeneration and contribute to generalization of the tubercle and emaciation. The transient infection of the blood with the pure tubercle bacillus does not, however, lead to emaciation and marasmus, and hence the frequency of high condition in spite of extensive tuberculosis.

Ostertag gives the following as indicating blood infection: “When with emaciation there is evidence of recent blood infection, enlargement of spleen and all lymph glands, miliary tubercles of the lungs, liver, spleen and kidneys.” In the absence of these indications, though there may be numerous old standing tubercles, caseated, calcified or sclerosed, he considers that there is no reason to dread infection of the blood and carcass. Even a tuberculous intermuscular gland does not, in his opinion, condemn the adjacent muscle. When vomicæ (caverns) are present in the lungs and internal organs the flesh may still be used “if embolic tubercles of different ages, indicating repeated eruptions of tubercle bacilli into the blood stream are absent from the spleen and kidneys.” This meat is, however, to be sterilized before marketing (Ostertag).

The United States Bureau of Animal Industry orders the destruction of all cases of “extensive or generalized tuberculosis;” “any disease or injury causing elevation of temperature or affecting the system of the animal to a degree which would make the flesh unfit for human food;” also “any organ or part of a carcass which is * * * affected by tuberculosis * *.”

In most countries of Europe even emaciated animals are used for food for animals or even man, provided the wasting is not too extreme. The carcass must, however, first be subjected to a temperature of 230° F. for a period of three hours. This is sold in a special market as low priced meat and labelled as such. Ordinary cooking does not always sterilize, as Martin and Woodhead, like Vilemin, found living bacilli in the centre of a cooked six-pound roast.

TREMBLING IN SHEEP. LOUPING-ILL. INFECTIVE MYELO-MENINGITIS. IXODIC
TOXÆMIA.

Definition: infective, tick-borne disease, characterized by
meningo-myelitis. Animals susceptible: sheep, and possibly swine
(Meek, Greig-Smith) and cattle (Williams). Known in North Britain only
in spring (in Skye also in autumn), on rough pasture with much brush,
and wood ticks, (Ixodes ricinus, erinaceous, marginatus or other).
Experimental infection. Bacteriology: Bacterium fluorescens β and γ
found in exudate and infecting. Accessory causes: dried grass of
previous year, brush, low condition, cold, youth. Symptoms: incubation
10 to 30 days; impaired innervation, hyperæsthesia, timidity,
excitability, trembling, jerking, lack of coördination and balance,
falling, convulsive struggling, jumping, rolling of eyes, stiffness,
opisthotonos, paresis, paralysis of hind—later of fore limbs, apathy.
Wry neck, arched back, stiff joints. Diagnosis from _myelo-meningitis_
by its enzoötic appearance, in spring, on tick infested ground: from
_paralytic rabies_, also by absence of that disease locally; from
_tetanus_ by its general prevalence, the absence of tonic spasm, and
presence of palsy; from _braxy_ by the lack of emphysematous
swellings, and of speedy sepsis; from _anthrax_ by usually healthy
spleen and its confinement to sheep. Lesions: cerebral meningitis with
encrease of subarachnoid fluid, of myelon, reddened, softened, also of
other serosæ, stomach, bowels, liver and kidneys. Prevention: destroy
ticks in winter by burning grass and brush, by ploughing and cropping;
or fence off ½ the pasture one year and the other half next; or lime
soil; or dip repeatedly in April, May and June to keep off ticks;
avoid moving sheep in these months: Give liberal feeding. Mortality 10
to 20 per cent.

_Definition._ All infective disease of sheep, inoculated by ticks, and producing a meningo-myelitis, with drowsiness, hyperæsthesia, irritability, paresis and other nervous disorders.

_Animals susceptible._ This is almost exclusively a disease of sheep, yet Meek and Greig-Smith claim to have seen it in swine that have eaten the raw carcasses of _louping-ill_ sheep, or that have ranged the tick infested pastures, and in rabbits inoculated with the microbe from the wound caused by the tick. W. Williams claims to have seen well marked cases in cattle, and heard of cases in horses and swine. He speaks, however, rather obscurely of “_the tick disease_” and seemingly includes in this all affections inoculated by ticks.

_Geographical Distribution._ This disease has been hitherto described as existing in the northern part of Great Britain only, but given the presence of the tick, and of the infection which it carries and the malady might easily be extended indefinitely. It is known to prevail in Northumberland north of the Tyne, in Kirkcudbright, Dumfries, Ayrshire, Lanark, Peebles, Roxburgh, Berwick, Argyle, Inverness, and Ross. In Berwick it is less prevalent than in the other countries named, while in the Western Isles it is not only widely spread rising on the hills 2000 feet or as high as the sheep range, but in Skye there are two distinct outbreaks, in spring and autumn respectively, apparently coinciding with the appearance of two successive generations of ticks. This may be due to the prevalence of warm winds from the Gulf Stream. Further investigation will doubtless show a much wider distribution—the author has seen an affection bearing the same general characters on the spurs of the Lammermoors in East Lothian, and the supposed adaptation of the Norse word _hloupa_ (staggering) suggests that it is probably not unknown in Scandinavia. W. Williams notes its prevalence on the Silurian formation, but ticks confine themselves to no geologic stratum, and the tick is the main agent in carrying infection.

_Causes. 1st, Sheep Ticks._ The sheep tick is not the _ked_ (Melophagus ovinus) which is common on long wooled sheep everywhere and is an example of a wingless, degraded dipterous insect.

The sheep ticks, on the other hand, are true ixodes, and of the same family with our common wood tick and of the cattle tick (boöphilus bovis) of the Southern States and the West Indies. The ticks collected from the sheep by W. Williams were identified by Mr. Moore, of the British Museum, as ixodes ricinus, ixodes erinaceous and ixodes marginatus. Those obtained by Meek and Greig-Smith showed the following characters: The male is 2.48 mm. long, by 1.30 mm. broad; the female is 5 to 5.5 mm. long, by 3 mm. broad, or when gorged with blood, 10 mm. long, by 7 mm. broad. The fasting female is yellowish green, and when full of blood, blue. Following the rule of their genus, the mature tick has eight legs, the larva but six. The fasting larva has head, legs and dorsal plate (scutellum) brown, the remainder of the body yellow. Scattered hairs appear on the body, legs and maxillæ.

In all ticks the rostrum is a characteristic feature. It consists centrally and interiorly of a dart covered below and on each side by rows of teeth turned backward, which, when imbedded in the skin, hold so firmly that the parasite may be pulled in two in any attempt to pull it out. Above this dart and on the two sides lie the cheliferæ (horns), each furnished with three or four teeth turned outwardly and more or less recurved, by which the dart is worked into the skin. Finally, on the lateral sides of this central apparatus, are the two maxillary palpi, which are not inserted into the skin, but applied against it and operate as feelers prior to and during the insertion of the dart and cheliferæ. The maxillary palpi are club-shaped and soft.

Ticks pass through three moultings before they attain to the sexually mature eight-legged form, and though the hexapod larvæ attach themselves to animals and irritate the skin by their bites, it is only the mature, impregnated egg-bearing female that lives exclusively on blood and sucks this to excess.

While given species of ticks show a preference for particular genera of animals, yet ticks generally in their vagabond life will leave the long grass and brush where they have been hatched to become temporarily the guests of any passing animal. It is, therefore, premature to seek to identify any single species of tick as the only bearer of the infection, and it is quite possible that any one of several species may contribute to its propagation.

_Experimental Infection by the Tick._ W. Williams muzzled four sheep from a healthy district and turned them for several hours a day on a tick-infested field, and two sickened—one on the eighth day and one on the sixteenth. Twelve ticks sent out of the district and put on a healthy sheep caused illness on the tenth day. In a second experiment with ten sheep, during a colder spring, when there were fewer ticks, no deaths occurred.

Meek and Greig-Smith turned twenty sheep on a tick-infested louping-ill pasture, six of the number wearing muzzles to prevent grazing, seven having been dressed with a mixture of sweet oil, 2 quarts; castor oil, 1 quart; train oil, 1 quart; pitch oil, 3 gills, and cade oil, 1 gill, while the remaining seven were unmuzzled and undressed. The muzzled sheep were regularly taken out and fed on food from a healthy locality. At the end of a fortnight oils were reapplied on the second lot (seven sheep). No ticks appeared on these sheep, while many were found on the undressed ones. On the fifteenth one of the unmuzzled and untreated sheep sickened and died with lesions of louping-ill. On the twenty-second day one of the muzzled sheep sickened, and died of louping-ill next morning. On the thirty-first day another of the muzzled sheep took ill and on the thirty-eighth was killed. It showed characteristic symptoms and lesions. The seven salved sheep, on which no ticks could at any time be found, remained healthy throughout.

_Bacteriology._ W. Williams describes a bacillus which he figures as forming filaments of very uneven breadth, with frequent branching (contrary to the habit of bacilli), and forming spores in clusters. These were obtained from the coagulum of the cerebro-spinal fluid and Meek and Greig-Smith conclude that the alleged mycelium was but the filaments of fibrin.

McFadyean found pus microbes.

Meek and Greig-Smith (Veterinarian, 1896–7) found in the black bloody swellings under the skin, where the ticks had inserted their proboscides, a variety of microbes which in pure cultures did not provoke louping-ill. These included staphylococcus cereus albus, sarcina lutea, bacterium putridum, bacterium coli commune, micrococcus sulphurous, micrococcus bicolor, and micrococcus caudicans. He also found penicillium glaucum. Two organisms allied to the bacterium fluorescens and designated as β and γ (G) respectively, were found in these sores and produced in rabbits and sheep nervous disorders and lesions which could be fairly identified with louping-ill. These are about 1.5 to 1.7μ long by 0.7μ broad, and chromogenic with a special fluorescent appearance. Microbe β inoculated on a rabbit caused on the second day rhythmic movements of the head downward and to one side, the eyelids closing as the head dropped, as if the animal were constantly falling asleep. In another rabbit it caused stiffness of the legs only and in a third it had no effect. Microbe γ when cultivated ærobically was harmless to rabbits, but when grown anærobically on mutton bouillon to which a drop of blood had been added, it caused on the second day general paralysis of the neck and limbs, spasmodic twitching of the muscles, dyspnœa and feeble heart action. Two rabbits which survived the early effects developed large axillary and inguinal abscesses four months later.

A lamb inoculated with the bouillon culture of γ showed after thirteen days, lameness of one hind limb, with paresis, and a disposition to fall to one side or the other. Two months later, when it had greatly improved, a second inoculation of microbe γ grown anærobically in bouillon and blood, caused, on the third day, a severe aggravation of the lameness.

_Accessory Causes._ Much depends on the abundance of old dried grasses of the previous year in which the larval ticks may hibernate. Land that has been burnt over in winter, that is cleared of brush, or in which the aftermath has been killed by free salting or liming will be largely cleared of the ticks.

Whatever disturbs or undermines the general health lays the system open to the disease and many flockmasters in tick-infested districts have succeeded in greatly reducing the mortality by feeding sound hay and oats in winter. Sudden changes of weather have long been noticed to coincide with outbreaks of the disease. A change to cold and wet is especially dangerous as causing a chill and robbing the system of its tone and vigor. But a sudden access of warm spring weather, especially if at the same time moist, may have a decidedly predisposing effect by lowering the general tone. A fatal paresis common in the flocks of New York, in the absence of ticks, shows a similar tendency to select the atonic animal. This occurs mainly in spring, when the sheep have been shut up in close confinement for weeks or months, with flaccid muscles and fatty livers, and above all if they are in advanced pregnancy with twin lambs, and if their fleeces are extra heavy. In both affections the majority of the flock escape, while those that are specially predisposed succumb. Lambs suffer most, doubtless because of relative weakness, and on account of their innate and unexhausted susceptibility.

_Symptoms._ After an incubation varying from ten days to thirty some impairment or disorder of the innervation is shown, varying widely, however, in different cases.

The two names “trembling” and “louping-ill” long used by shepherds as characteristic of the disease indicate spasmodic disorder of a clonic kind, the paresis which is essentially passive having been very naturally overlooked, or held to be subordinate. There is hyperthermia the temperature rising at times to 105° or higher, and often marked hyperæsthesia and excitability at the outset. On approaching the patient it is very much frightened, and when caught, struggles and twitches in a remarkable manner or trembles violently. If merely raised or disturbed the trembling or clonic spasms are very marked, the nose is jerked forward and upward from the contraction of the muscles attached to the occiput; the legs may be lifted jerkingly as in stringhalt; when raised they are moved stiffly or sway uncertainly before the foot is once more planted; or the sheep loses its balance, falls to the ground and struggles convulsively in its efforts to get up and escape. As the result, it will in certain cases jump to its feet, rising meanwhile to an undue height in the air. In other cases there is squinting or rolling of the eyes, and movements of the jaws with frothing from the mouth. Or the spasms may be tonic affecting especially the muscles of the back and loins, and causing extreme stiffness or rigidity or even opisthotonos. Lambs are unable to suck.

But whether the early spastic symptoms are well marked or not, paresis and even paralysis set in sooner or later. This usually begins as paraplegia, or exceptionally one limb only may be affected at first, causing the animal to walk on three legs. For a time the fore limbs may be free, and the patient attempts to move by dragging the hind limbs, which are extended backward. When the fore limbs become involved the animal remains down helpless and after awhile apathetic. Temperature and sensibility are both greatly lowered in the paralyzed limbs. Sometimes the spasms are lateral and the head may be drawn to one side.

In the animals that survive the early attack, there is likely to remain some lasting deformity, such as wry neck, arched back, stiff or swollen joints. Abscesses, which appeared in the inoculated rabbits after a lapse of four months, are a not uncommon sequel in sheep, the pus collecting in the neighborhood of a joint, or of the lymph glands of the axilla, inguinal region, breast or shoulder.

The succession of symptoms are in the main such as are observed in other cases of myelo-meningitis, first exalted function and later depressed and abolished.

_Diagnosis._ From other forms of myelo-meningitis it may be distinguished by its enzoötic occurrence on tick-infested pastures, which already have a reputation for causing this malady, by its appearance only in the season of the development of the tick, by the presence of the tick or of its sores on the skin, and by its entire absence from adjacent fields which are free from ticks. From paralytic rabies it is differentiated by the same conditions, and as a rule by the absence of rabies from the district and of any evidence of a bite. In tetanus the tonic persistent nature of the spasms, the absence of paralysis, the marked spasms of the muscles of the eye, and the usually isolated condition of the case should prevent any confusion. Braxy is to be distinguished by its emphysematous swellings near the surface of the body, and by the comparative absence of hyperæsthesia, spasm, or paralysis. The carcass in braxy undergoes much more rapid decomposition. Anthrax is more rapidly fatal, shows no such marked nervous disorder, has a dark, nonoxygenated and often incoagulable blood, an enlarged sanguineous spleen, and the characteristic anthrax bacilli. It attacks the larger herbivora as readily as the small.

_Lesions._ The most constant and striking lesions are found in the nerve centres. In many cases there have been found cerebral meningitis, involving the choroid plexus (Fair, Hamilton, Klein, Murray, McFadyean) with an encrease of the ventricular and subarachnoid fluid (Murray, Hamilton, Williams). The exudate may be yellow or rosy from contained blood globules (Klein). The meninges are thickened and the seat of ramified redness. In the region of the spine inflammation is found not only in the meninges but also in the cord, which may be blood-stained, softened (Mathewson, Goodwin, Robertson), or in older cases indurated (Robertson, Hamilton, Williams, Young). In this last condition there is a sclerotic condition of the neuroglia, and it may be a distinct atrophy. The exudate is usually abundant and more or less coagulated into a soft, diffluent jelly.

In many cases there is inflammation of the serous membranes of the chest (pleura, pericardium, endocardium), and even of the lungs (Fair, Hamilton, Klein). In some instances there has been inflammation of the stomach and intestines (McFadyean), liver and kidneys (Klein), and enlargement of the spleen has been noted. The most constant lesions appear to be those of the nerve centres, but the wide variety of organs involved in different cases sufficiently accounts for the variability of symptoms.