Chapter V: Translation of Selected Passages From the Anatomy, with Commentary

(_a_) THE HEAD

Tractate i, Chapter 2

(folio 5 verso) There are ten layers of the head.

The _first_ is the _hair_ made by nature for the better protection of the head from external things, and also for beauty.

The _second_ part is the _skin_, which has here to be very thick, so that the hair may be firmly embedded, having its roots thick and long; and also to be a better shield and covering for the bone and brain, since there is no muscular part here.

The _third_ part is the _flesh_, developed only on the face, the temples, and about the jaws, not on the other parts.

The _fourth_ part is an external membrane called _almochatim_ [Arabian term for cranial periosteum] which, when the skin is raised, appears to be continuous and covers the whole cranium. And nature made this membrane firstly so that the skin which is soft should not come into contact with the hard bone, secondly that the bone of the head should have sensation through it, and thirdly that the internal membrane of the head, called _dura mater_, should, by means of this membrane, be attached to the bone of the cranium by certain nerves and ligaments. These, issuing through the commissures of the bones, have thus their origin in the aforesaid internal membrane, while on emerging through the bone, they weave themselves into or rather compose the external membrane called _almochatim_.

The _fifth_ part is the _skull_. This is a bone like a cap, inside the cavity of which is located the brain. In the skull are four bones sutured together. Nature made the skull not of one but of many pieces, firstly, so that if harm should fall on one part it might not spread to the others; secondly, so that by their joints or rather sutures [Italian _cusiture_=sewings], the humours of the brain might be the better exhaled; and thirdly, so that when there is need of applying medicines, these might the better penetrate to the parts within.

Hence it is that four pieces of bone are sutured and joined together by nature in a denticulate fashion, so that they might be the firmer and stronger. Nor are they bound with ligaments as are the joints, for these would not have been so strong, and furthermore the bones of the head do not need to move.

These sutures are five in number, three being true and two false. The true sutures are those which pass right through the bone, while the false do not. Of the true sutures one is in the anterior part and is called _coronal_; it is made like the letter C, and stretches from right to left of the head, the two wings of the C being directed towards the forehead. The second true suture extends along the length of the head, beginning from the coronal and reaching the back part of the head. It is like a shaft or rather arrow that goes backwards from the brow, wherefore it is called _sagittal_ ----(. The third true suture is in the posterior part and is called laudal, for it is made like a Λ, the letter called by the Greeks _lauda_. The sagittal suture extends from the coronal to the lauda ❯----(.

The false sutures are two, one on each side. They are called _cortical_ because they do not penetrate.

Now if we consider these five sutures we shall see that there are four bones articulated together. One is the forehead bone [frontal] which begins at the coronal and ends below at another suture, which itself begins as a branch of the coronal suture and proceeds by way of the eyebrow to the corresponding branch [of the other side] Ɑ.

A second bone is behind and terminates at the laudal suture. There are two other bones which form the temples. These terminate at the false sutures which themselves begin at the laudal and end at the coronal suture.

The _sixth_ part [of the head] consists of two membranes. One of these is called _dura mater_, and lies in contact with the cranium. The other is called _pia mater_ and is in contact with and covers the brain. And nature contrived it thus, having great solicitude for this latter member, that while close to the bone, it should yet not be touched by it. Wherefore, taking due precautions, she made the one [membrane] harder than the other. Furthermore she made two membranes, so that if harm befell one of them, it might not be communicated to the underlying brain.

In the _pia mater_ are woven certain veins by which the brain is nourished. [The brain is] everywhere covered by it except on the posterior part; because this part being dry, it has no need of this membrane, as have the anterior and middle parts. The two membranes in many places penetrate the substance of the brain, dividing it into a right and a left, a front and a back section. By this division, divers cells or rather small chambers are made therein, in which the soul (_anima_) performs its divers operations, for which reason it is necessary that these parts should be of different structure.

When the two membranes are raised, the _seventh_ part of the head, namely the brain itself, appears. The brain is wrought by nature so that the _vital spirit_ from the torrid heart should be tempered by its cold, for here it is converted into _animal spirit_, which is the beginning of the perceptive (_cognoscitiue_) and motive processes.

The brain is of a substance like marrow, white, soft, and viscous, and from it the nerves arise. The anterior part is moister, softer, and less cold than the posterior because the senses [_sentimenti_ = senses + mental processes], which are themselves moist and soft, have here their origin. In the posterior part the motor nerves arise, and it is therefore drier and firmer.

The brain is divided into three parts or ventricles. The first ventricle or anterior part is itself divided into two, right and left, and is moreover larger than any of the other ventricles, for in this first ventricle nature has placed the two faculties subservient to perception (_al cognoscere_). One of these is called _common sensation_ (_senso comune_); in it the external senses terminate as at a centre and deliver the _images_ or rather _species_ of sensible things, so that this faculty may perceive and distinguish between one sensible thing and another, and also comprehend the operations of particular senses; which two things none of these [senses of themselves can do]. The other faculty of the first ventricle is called _fantasia_ and by some _imagination_; it retains and preserves the _species_ of sensible things in the absence of the material objects themselves.

When thou examinest the first ventricle thou wilt see three things before thou comest to the second ventricle.

[_a_] The first is itself double, and is formed of the very substance of the brain, so that it forms the base of the anterior ventricle both right and left [= corpora striata].

[_b_] To the side of this is another thing like a subterranean worm, red as blood, yet tethered by certain ligaments and nervelets [= choroid plexus and taenia semicircularis]. And this worm when it lengthens itself closes these passages, and thus blocks the path between the first ventricle and the second. Nature has wrought it thus, so that when a man wills he may cease from cogitation and thought; and similarly when, on the other hand, he would think and contemplate, this worm contracts itself again and opens these passages and thus frees the way between one ventricle and another.

[_c_] The third structure is a little lower and is a _lacuna_ or rounded concavity [= infundibulum]. In the middle of this is a hole which passes down towards the palate, and this lacuna provides also a direct passage which descends from the middle ventricle to its _colature_ [= sieve-like structure, i.e. certain parts of the sphenoid bone]. And this lacuna has around it certain large round eminences which support the veins and arteries that ascend to the ventricle. This passage is wide above and narrow below, and by it the first and second ventricles purge themselves of their superfluities, but the anterior part [of the first ventricle] purges itself more by the colature of the nose [= cribriform plate]. Thus nature has made two passages to cleanse the superfluities of the brain.

When thou hast seen these three structures there will appear the second or middle ventricle which is as a passage and transit from the anterior to the posterior ventricle. Here are two faculties. One, the _estimative_, deduces [Italian _elicere_] the insensible from the sensible. The other, called the _cognitive_, comprehends both things sensible and things insensible, synthesizing and analysing them (_componendo e dividendo_). These [two] faculties in the middle ventricle minister to the intellect. Now all the other faculties described, and even the power of memory, are found in brute animals, but this [intellectual power] is encountered in man alone.

Now will appear the third ventricle in the posterior part; and it is hard, for it gives rise to the greater part of the motive nerves which are of a strong and firm nature. This ventricle is pyramidal in shape, and culminates in an apex directed upwards where images of visible things (_spetie_) are conserved, for these are better stored in a strait than in an ample space; but the part below is wide to receive these images, which are better received in an ample than in a strait place. This ventricle has two functions: it gives rise to the spinal cord [_nucha_, an Arabian term] and motor nerves; and it is also the storehouse of the _memorative_ faculties.

From what [has been said] it will be apparent that when the back of the head is injured, the memory immediately suffers; when the middle part is injured, the estimative and cognitive faculties suffer; and when the anterior part is injured, the faculties of common sensation and of imagination (_fantasia_) suffer. And thus it is that the doctors have become aware of the location of these powers.

This being disposed of, thou wilt next raise the brain carefully so as not to break the nerves. Commencing now with the part in front, there will first appear two small fleshy protuberances like two nipples, of like substance to the brain in which they originate, and covered by a thin membrane, the pia mater. These are the olfactory organs, wherein is the sense of smell.

From the brain arise seven pairs of nerves. Proceed therefore farther with the anterior part, and thou wilt see the first pair of these nerves, which are large, and called the _nervi optici_. These have their origin in the front ventricle of the brain and proceed towards the eyes. But before they pass through the pia mater, they join together, and at their place of union there is a perforated spot. Galen maintains that these nerves only join or rather unite, but do not intersect, so that the nerve that comes from the right after union returns again towards the right, and similarly with the nerve coming from the left, which after the union returns towards the left eye.[185] But Rhazes maintains the contrary,[186] although the opinion of Galen is the more common. These nerves are subservient to sight, and they are united so that the images of the things received by the two eyes and conveyed by the two nerves should return in unity; so that one thing should not appear as two.

After these two nerves, raise the brain towards its middle and thou wilt see another pair of nerves, thin and firm, which also go to the eyes, to give them voluntary movement, controlling certain muscles.

Farther on thou wilt see the third pair of nerves, one part of which goes to the face to give it sensation and voluntary movement, while another part goes to give taste to the tongue. Yet a third part of these nerves mingles with the fourth[187] pair of nerves, and together they descend to give sensation to the diaphragm, stomach, and other viscera. A certain part also of the fourth[187] pair of nerves goes to give sensation to the palate.

Then there is the fifth pair of nerves [which] go to the _petrous_ bone around the ear; and of these nerves there are framed in the ear-holes certain membranes, which are the organs of hearing.

Next there is the sixth pair of nerves, which divides into three parts. One part goes to the muscles of the throat, the second to the muscles of the shoulders, and the third and largest descends to the epiglottis and to the diaphragm, and spreads into the chest, the heart, and the lungs, accompanying the nerves of the third pair. From the nerves of this sixth pair which go to the epiglottis arise the nerves of the voice, called _reversive_.

The seventh pair of nerves arise at the back of the brain and give voluntary movement to the tongue.

Of these seven pairs of nerves, the first two pairs originate in the anterior part of the brain, the third pair originates between the anterior and posterior parts, while the remaining four pairs originate in the posterior part.

Proceeding still farther, the brain may be completely raised, and the eighth part of the head will appear, that is, the two membranes situated below the brain. When these in turn are raised there will appear the ninth part, which is a certain net called _rethe mirabile_, because it is composed of exceedingly strong and marvellous texture, augmented by certain very fine arteries which are branches of arteries that ascend from the heart, and are called the _apoplectic arteries_. In these arteries of this net is contained the vital spirit, sent from the heart to be changed to animal spirit. That the spirit may be the better modified and distributed, nature made these arteries very fine, and separated them into very small branches so that the spirit should be minutely divided. Nature placed the rethe mirabile under the brain because it was necessary to guard its site carefully, and also that the moist vapours of the brain which fall upon the net, obstructing it, should induce natural sleep.

After all these things thou wilt see the basal bone which is the tenth and last part of the head, and called _basilar_, because it is the base and foundation of the whole head; and it was made hard so that the superfluities which descend to it should not putrefy it. This bone can be seen to be formed of many other bones articulated together. It is divisible into the petrous bones and the bones of the nose and eyes and two other lateral bones which can only be seen by means of disarticulation. [Folio 10 verso, line 22.]

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From the _Anatomia_ of Johannes Dryander, Marburg, 1537.]

The ten parts or layers of the head are a commonplace of the anatomy of the period, taken from Avicenna. We may illustrate the division by the crude contemporary diagram of Fig. 11, which is improved in the later drawing reproduced in Fig. 12.

Manfredi’s account of the brain itself is amplified from Mondino. The division of this organ into three ventricles, each associated with a corresponding division of the mental functions, was very familiar to medical writers of the fifteenth century. The idea is found among Western writers as early as St. Augustine (354-430), and is encountered in the writings of Roger Bacon (1214-94). It had long been popularized in mediaeval psychology by the writings of Albertus Magnus (1206-80). The anatomical distinction is found in Haly Abbas, Avicenna, and Rhazes, and in some of the best MSS. of the latter writer a rough diagram of the ventricles is given.[188] These writers are all clearly indebted to the anatomy of Galen,[189] but on the psychological side Albertus Magnus probably drew mainly either from Ghazali[190] (1059-1111), who in turn derived his inspiration from Nemesius (fourth century) and Johannes Damascenus (died 756), or else from early writers of the Salernitan tradition, such as Constantine[191] (eleventh century), or Petrocello[192] (twelfth century), who drew largely on Theophilus (seventh century).[193]

This outline of a tripartite division of the brain and its cavities was closely followed throughout the Middle Ages, as was also the curiously naïve and excessively ‘materialistic’ psychology to which it gave rise, and which Manfredi adopts. We illustrate his views of the relationship of the different parts of the brain and their parallelism in mental processes, from a series of diagrams extracted from contemporary works (Figs. 13-18).

The brain was regarded by mediaeval and early Renaissance anatomists as having two channels of discharge through which the _phlegm_, the especial product of this organ, could be evacuated when in excess. One of these channels communicated with the anterior ventricle of the brain and poured its secretion into the nose. It may be identified with the _anterior colature_ or cribriform plate. The second, the _lacuna_, led down from the second ventricle and poured its secretion into the pharynx. It may be identified with the infundibulum, pituitary body, and ‘cella turcica’. The term ‘pituitary’ which we still use is derived from its supposed association with the ‘pituita’ or phlegm. At an early date this process was connected with the four humours (Fig. 14). The rest of the description of the brain can be easily followed. The comparison of the choroid plexus to a worm is very common. The suggestion originated with Galen and was developed by the Arabians.

COMPARATIVE TABLE OF ANCIENT AND MODERN NOMENCLATURE OF CRANIAL NERVES.

_Mondino and Manfredi following Galen, |
especially in the_ περὶ χρείας τω̑ν ἐν | _Modern usage._
ἀνθρώπου σώματι μορίων. _De usu partium |
corporis humani._ |
---------------------------------------+----------------------------
Not regarded as separate nerves. | I. Olfactory nerves.
---------------------------------------+----------------------------
I. τὰ μαλακὰ νευ̑ρα τω̑ν ὀφθαλμω̑ν. | II. Optic nerves.
---------------------------------------+----------------------------
II. τὰ κινητικὰ τω̑ν ἀμφ᾽ αὐτοὺς μυω̑ν. | III. Oculomotor nerves.
---------------------------------------+----------------------------
Not mentioned. | IV. Trochlear nerves.
---------------------------------------+----------------------------
III. τρίτη συζυγία.    }   | V. Trigeminal nerves.
IV. τετάρτη συζυγία. }   |
Mondino and Manfredi confuse |
Galen’s fourth pair and Galen’s |
sixth pair. |
---------------------------------------+----------------------------
Not mentioned by Manfredi. By | VI. Abducent nerves.
Galen probably united with II. |
---------------------------------------+----------------------------
V. πέεμπτη συζυγία.    |{ VII. Facial nerves.
|{VIII. Auditory nerves.
---------------------------------------+----------------------------
VI. ἕκτη συζυγία.   | {IX. Glossopharyngeal
| nerves.
| { X. Vagi.
| {XI. Accessory nerves of
| Willis.
---------------------------------------+----------------------------
VII. ἑβδόμη συζυγία.     | XII. Hypoglossal nerves.
---------------------------------------+----------------------------

The nomenclature of the cranial nerves adopted by Manfredi is taken from Mondino and is almost identical with that of Galen, whose classification is summarized above.[194] Manfredi’s description of Galen’s fourth pair is confused and inadequate, but his account of Galen’s sixth pair is an improvement upon Mondino.

The ‘rete mirabile’ is an interesting survival of Galenic anatomy. This structure is hardly present in man, but is developed in the lower animals, and especially in calves, upon whose bodies Galen worked. The father of physiology regarded the ‘rete mirabile’ as the place where the psychic pneuma was elaborated.[195] Galen’s findings in the lower animals were assiduously transferred to the human body, to which his descriptions are much less applicable, while his views on the pneuma lasted in more or less misunderstood form well into the seventeenth century.

(_b_) THE EYE

Tractate i, Chapter 3

(folio 11 recto) The socket of the eye is not over-depressed, for it has to receive the images (_spetie_) of visible things. Nor does it project greatly, lest it should be liable to injury from exterior violence. For the eyes of man being very soft and susceptible, nature provided eyebrows as a shield above, and eyelids as protectors in front, and made moreover the projections of the maxillae and the nose, so that the eyes should be guarded on every side. So great was the solicitude of nature for these members.

Seven are the tunics of the eye and three its humours. Three front coatings join with three coatings at the back like six shields, the edges of every pair joining each to each, the outer being larger and containing the others. The seventh tunic is largest of all, and encloses the whole eye, and therefore it is called _conjunctiva_ because it joins and surrounds the whole eye except the place where the pupil is, and that small part [is covered] by the cornea. Now this first tunic where it covers the outside part is seen to be white.

The second tunic in its front part is called _cornea_ because it resembles horn in its substance and colour; and this covering is transparent, so that the images of visible things may penetrate through it. And it is also solid and large and composed of four membranes, so that being near external things it should not receive hurt. With this [corneal tunic] is united posteriorly another tunic [the third] called _sclerotic_, i.e. hard. These two coverings have their origin in the membrane about the brain, that is in the dura mater, just as the first tunic arises from the membrane over the skull, called _almochatim_.

The fourth tunic as to its front part is called _uvea_ [because] it is like a seed of a black grape, and in its midst is a hole called the pupil. Nature made this tunic opaque so that the visual spirit should be conserved and not dissipated by the light outside. Moreover nature made the opening in the tunic that the image might penetrate freely; while it is narrow, so that the visual spirit should be concentrated. Thus when the said pupil, or rather hole, dilates more than usual, either naturally or accidentally, the sight becomes imperfect. [The uveal tunic] joins posteriorly the fifth tunic, called _secundina_ because it is made like the after-birth, i.e. the membrane in which the child is enveloped in its mother’s womb, and it arises from the pia mater.

The sixth coating in front is called _arachnoid_ because it is formed after the manner of a spider’s web, and posteriorly it joins the seventh coating, called _retina_, because it is made like a net.

Between the uvea and the arachnoid anteriorly there is a humour called _albugineus_, like the white of an egg, to moisten the eye and to preserve the convexity of the cornea. In a dead man this humour dries up, and the cornea falls and is flattened, and then the vulgar say that there appears a curtain before the eyes which is an infallible sign of death. Also this humour holds the pupil open; therefore when it dries up the pupil contracts.

Between the two last tunics, i.e. the arachnoid and the retina, which have their origin from the optic nerve, there are two humours. These are the _vitreous_ humour, so called from its likeness to liquified glass, and the _crystalline_ humour, from its likeness to a crystal. This is also called the _grandid_, because it is like a hailstone; and it is somewhat hard and round, but flattened anteriorly where it receives the images of visible things, and posteriorly pyramidal shape and pointed. And here is completed the act of seeing. In the posterior part it is surrounded by the vitreous humours by which it is nourished. The crystalline humour is convex anteriorly and the vitreous posteriorly. And the optic nerves come to the eyes and convey the images seen by the eyes to [the seat of] common sensation and to the other internal faculties. [Folio 12 verso, line 7.]

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From G. Reisch, _Margarita philosophiae_, Leipzig,? 1503. Showing the seven tunics and three humours of the eye according to the doctrines of Renaissance anatomists.[196]]

A great deal of attention was paid by the Arabians to the diseases and the structure of the eye, and the essentials of Manfredi’s description are to be found in Rhazes, Hunain ben Ishak, and Haly Abbas. The tradition presented by these writers passed early into Western science, and is reproduced, for example, in the works of Constantine Africanus and in the well-known anatomy to which the name of Richardus Anglicus (Richard of Wendover) has become attached[197] (cp. Fig. 19). Avicenna’s description of the eye is somewhat different, and gave rise to the tradition reproduced in the works of John of Peckham and of Roger Bacon (Plate XXXVIII _a_), and it influenced the views of Leonardo and even perhaps of Vesalius (Fig. 20). The views on the anatomy of the eye expressed by Rhazes, Hunain ben Ishak, and Haly Abbas were, on the whole, more widely accepted than those of Avicenna.

THE ANATOMY OF THE EYE

From Vesalius, _De humani corporis fabrica_, Basel, 1543, p. 643. A, Crystalline humour; O, Albugineous humour; C, Vitreous humour; N, Cornea; Q, Conjunctiva; M, Sclerotica; G, Secundina; H, Uvea; K, Arachnoidea; E, Retina.]

The treatment of the eye was always felt to be hardly within the range of the ordinary practitioner of surgery, and its structure, as we learn from Guy de Chauliac,[198] was not usually treated in the general course of anatomy. The custom was rather to refer the student to special works such as those of Jesu Aly or of Alcoatim.

Manfredi’s description of the anatomy of the eye is that generally accepted at the end of the fifteenth and the beginning of the sixteenth centuries, and is unusually clear for its date. It represents a considerable advance on such writers as Henri de Mondeville (1260-1320)[199] or the pseudo Richardus Anglicus, and is far superior to the descriptions of the eye dating from the fourteenth and fifteenth centuries recently brought to light by Sudhoff.[200] We reproduce as illustrating Manfredi a diagram taken from the _Margarita philosophica_ of Gregorius Reisch (died 1525). This represents the earliest printed figure of any value of the anatomy of the eye (Fig. 19).[201] We give for comparison the figure from a thirteenth-century MS. of Roger Bacon (Plate XXXVIII _a_), representing the rival tradition of Avicenna and Alhazen that influenced Leonardo da Vinci and other contemporaries of Manfredi. These figures may be compared with that of Vesalius (1543, Fig. 20), whose description of the eye is less free from traditional bias than are most parts of his epoch-making work.

In reading any early description of the eye, it is to be remembered that until the nineteenth century the ‘emanation theory’ prevailed. Light was regarded as of the nature of a stream of particles emitted from the object seen, and the act of vision was considered as a collision of this emanation with an emission of something from the eye itself, called in mediaeval writings the ‘visual spirit’.

(_c_) THE HEART

Tractate ii, Chapter 3

(folio 19 verso) Then you will see in the midst of the lung the heart, covered by its membranes. [It is thus situated] that the air attracted by this lung should cool it, and that thus the heat and spirit of the heart be tempered. This member is the most important of the four [principal members], because it is the first to live and the last to die. It is of medium size compared with the other members of man, but compared with the hearts of other animals it is very large, because man, in a quantitative and not an intensive sense, has more natural heat than other animals. It is pyramidal, that is in the form of a flame; because it is of excellent warmth, therefore it is necessary that it should be of a shape resembling a flame. Its figure is also called ‘pine-shaped’, because it is wide below and narrow above, being thus formed that distinction could better be made between its cavities or ventricles; moreover, had it been made of a shape all uniform as is the lower part, it would be too heavy and ponderous.

This member is situated in the middle of the entire body, measured in every direction; that is, in the middle between the upper and lower parts: in the middle also between front and back and right and left, like a king standing in the midst of his kingdom, and this was done that it might give the strength of life equally to all the members; and although the heart as regards its foundation and base be in the middle, yet its point declines to the left below the left breast, so that it warms the left side as the liver warms the right.

This member is sustained and strengthened by a certain cartilaginous bone. For since it is continually moving, it needs some point of purchase to support it in its movements. Moreover, it has a certain fatty layer on the outside which prevents the heart from drying and keeps it moist: and there are certain veins and arteries dispersed through its substance: and it is formed also of a kind of hard flesh so that it may sustain many and forceful movements; also it is formed of longitudinal, latitudinal, and transverse fibres, so that it may have the power to attract, retain, and expel.

This member has three ventricles or chambers, like the brain. One ventricle is on the right side, the second on the left, and the third in between. The right ventricle towards the liver has two orifices. One is towards the liver and is very large. Into this there enters a vein called _vena chilis_, which arises in the convexity of the liver and brings the blood from the liver to the heart. In that right ventricle the blood is purified, and then sent by the heart to all the other members.

Now since the heart attracts by this orifice of the _vena chilis_ more than it expels, therefore nature ordains that in the moment of contraction when the blood is expelled this orifice closes, and when the heart dilates it opens.

Moreover there are three little valves (_hostiolitti_) or doors opening from without inward, and these valves are not very depressed; so that by this same orifice only part of the purified blood is expelled to the other members, because part goes to the lungs and the remainder forms the vital spirit; therefore nature ordains that these valves do not entirely close. From the _vena chilis_, before it enters the cavity of the heart, there arises another vein, which surrounds the root of the heart; and from it are given off branches which disperse themselves through the substance of the heart, and from the blood of that vein the heart nourishes itself.

The right ventricle towards the lung has another orifice into which opens the _arterial vein_, bringing the blood from the heart to nourish the lung: in this orifice also are three valves (_hostioli_) opening from within outward and closing from without inward, in the opposite way to the valves of the other orifice; and this is so that they should entirely close. Hence by this orifice the heart during the period of contraction can expel, and yet during the period of its dilatation cannot attract anything through it as was done in the first orifice.

The left ventricle of the heart has its sides denser and thicker than the sides or walls of the right ventricle; and this for three reasons: Firstly, because in the right ventricle is contained the blood, which is heavy, while in the left ventricle there is spirit, which is very light; therefore in order that the heart should not be heavier and more ponderous on one side than on the other, it was necessary to compensate in this manner, that is, that the left ventricle should be thicker in its walls than the right. In the second place, the spirit being more subtil and more volatile (_resolubile_) than blood, it needs a stronger habitation and better supports. Thirdly, the left ventricle is much warmer than the right, because in it is generated the spirit from the blood, by a great heat which makes that blood more subtil; and heat is better preserved in a substance that is dense and thick.

In the cavity of this ventricle near its root are two orifices: one is the orifice of an artery called _artharia adorti_ [= aorta], because it has immediate origin in the heart and because it is the source of all the others: by this artery the heart sends the generated spirit to all the members; and the very subtil blood is mixed with the spirit when the heart contracts. For which reason there are at the entrance of this orifice three valves, which close entirely from the outside inwards; and they open from the inside outwards, and this orifice is very deep.

The other orifice is that of the _venal artery_ which conveys the air from the lung to cool the heart and transports warm vapours from the heart to the lung as has been said above; and in this orifice are two valves which do not entirely close: and they are well raised so that they can better apply themselves to the sides [edges] of the heart when it sends out the spirit: these are marvellous works of nature, as is also the central ventricle of the heart, for this ventricle has not one cavity but many; these are small but wide, and more numerous on the right than on the left; and nature contrived thus, so that the blood which goes from the right ventricle to the left to be converted continually into spirit becomes thin in these cavities.

And by this thou canst see that four things have birth in the heart. The first is the artery called _adorti_, the second is the _vena chilis_, the third is the _arterial vein_, and the fourth the _venal artery_.

Also thou wilt see in the heart certain membranous parts like _auricles_, or rather like small ears, able to dilate or contract: these are contrived by nature in order that when overmuch blood or spirit is generated the heart can dilate so as to contain it; and also that the heart may contract when there is no such abundance.

And it is here that Galen asks, Why did not nature make the heart so large that it could contain every increase of blood or spirit without the addition of these membranes? Galen replies that this was first because the heart would have been too large and therefore too heavy; secondly, because as it is not always generating a great quantity of blood and spirit, if the heart had been too large, its cavity would usually have been empty: but these auricles dilate with the accumulation of blood or spirit, and contract with its decrease.

The heart is surrounded by a firm and nervous membrane, like a little house in which it is placed as in a tabernacle to defend it from accidents. This capsule is very dilated, that the heart in its dilations and movement may not be impeded thereby, and therefore nature made this capsule so that it should contain a certain dewy moisture with which the heart is bathed and moistened so that in its continual movement it should not become dry. For when this water be dried up, then the heart itself is desiccated, and emaciates and dries up all the body.

* * * * *

The description of the heart follows Mondino closely. Occasionally a phrase or two is reminiscent of Mondeville. The trite conception of the heart as a king in its necessarily central position was very frequently repeated by writers in the Middle Ages. To Harvey, who had a certain mediaeval element in his mentality, it seems to have appealed, and he used it in his _Prelectiones Anatomiae_,[202] and chose it to introduce his great work on the circulation of the blood.[203] The heart was similarly described as ‘flame-shaped’, because it was regarded as the source of animal heat. The idea that it is the first to live and the last to die comes from Aristotle.[204] The _bone_ in the heart also comes from Aristotle.[205] The idea was quite familiar to mediaeval anatomists, who frequently endeavoured to identify the _bone_ with the firm tissue around the orifices of the aorta and pulmonary artery. The reader may be reminded that a true ‘os cordis’ is in fact to be found in some mammalia.

Mondino, followed by Manfredi, describes the action of the heart and blood-vessels mainly according to the views of Galen, but without any very clear or connected statement. The ‘third ventricle’ especially has its origin in a misunderstanding.

This mythical structure is an attempt to combine the views of Aristotle and of Galen. Aristotle, who probably never dissected a human body, derived his anatomical conceptions largely from cold-blooded animals, in some of which the heart is provided with three cavities. He considered that the heart had three chambers, the largest being on the right, the smallest on the left, and one of intermediate size between the two. As far as they can be identified, the largest was the right ventricle plus the right auricle, the smallest or left chamber was the left auricle, while the intermediate cavity appears to have been the left ventricle.[206]

Galen’s description differed altogether from that of Aristotle. He tells us expressly and somewhat contemptuously that ‘it is no marvel if Aristotle erred in many anatomical matters, a man who thought forsooth that the heart in the larger animals had three chambers’.[207] Galen always describes the heart as having but two chambers, the right and left ventricles, a wholly subordinate part being assigned to the auricles. These latter were regarded as safety-valves, expanding to hold superfluous blood when the chambers of the heart to which they correspond become overfilled.

From the Roncioni MS. (Pisa 99) after Sudhoff.]

No third ventricle is described by Rhazes or Haly Abbas,[208] but Avicenna, in his _Canon_, makes an effort to combine the views of Aristotle and Galen. Speaking of the anatomy of the heart (lib. iii, fen. xi, chap. 1) he describes the ventricular portion as follows: ‘In the heart are three cavities, two large, and a third as it were central in position. So that the heart has [_a_] a receptacle [the right ventricle] for the nutriment with which it nourishes itself--this nutriment is thick and firm like the substance of the heart; [_b_] a place where the pneuma is formed [the left ventricle], being engendered of the subtil blood; and [_c_], thirdly, a canal between the two.’[209] A somewhat similar account is given in Constantine’s translation of Isaac.[210] The idea soon crept into European medicine, for in a Pisan MS. dating from the first half of the thirteenth century[211] a crude figure of a three-chambered heart is to be found (Fig. 21).

The first translator of the _Canon of Avicenna_, Gerard of Cremona, whose work appeared towards the end of the twelfth century, improved on his original. ‘In it [the heart] are three ventricles; two are large, and the third as it were between, which Galen called the fovea or non-ventricular meatus, so that there may be a receptaculum for the thick and strong nourishment, like to the substance of the heart, with which it is nourished, and also a storehouse for the pneuma (spiritus) generated in it from the subtil blood. And between the two are channels or meatuses.’[212] Henri de Mondeville (died about 1320), by going direct to Galen, avoided some of the errors of Avicenna, with whom, however, he still describes three ventricles.[213] Mondino does little but copy the Arabian, whom Manfredi also follows.

We may terminate our description of the mythical third ventricle by quoting from Bartholomew the Englishman. His encyclopaedia written about 1260 was translated into English in 1397, and printed by Thomas Berthelet[214] in the 27th year of the reign of Henry VIII (1535), when Bartholomew’s work was still extremely popular. Berthelet’s rendering runs as follows:

‘And the hert hath ij holownesses, one in the left syde, that
cometh sharpe: and one in the ryght side, that is within: And these
two holownesses ben called the wombes of the hart. And betwene
these two wombes is one hole, that some men call a veyne, other
an holowe way. And this hole is brode afore the ryghte syde, and
streyte afore the left syde. And that is nedefulle to make the
bloode subtyll, that commeth from the ryght wombe to the lefte,
and so the spirite of lyfe may be bredde the easelyer in the lefte
wombe.’

In order to understand why all these authors invoked the existence of the third ventricle, regarded by some of them as a passage between the other two, we must turn to the physiological beliefs of the age. It must be recalled that before the demonstration of the circulatory movement of the blood a certain amount of communication was believed to exist between right and left ventricles. The complicated nature of the ventricular cavities and the intricacy of the columnae carneae promoted the idea of the presence of minute passages in the interventricular septum. Even so astute an observer as Leonardo da Vinci considered that ‘the ventricles are separated by a _porous_ wall, through which the blood of the right ventricle penetrates into the left ventricle, and when the right ventricle shuts, the left opens and draws in the blood which the right one gives forth’ (Plate XXXVIII_b_).[215]

Although the third ventricle is described in all the twenty-five editions of Mondino, many of which are illustrated, they present no drawing of it except the wretched little diagram of J. A. Muelich (Johannes Adelphus) in 1513, which we here reproduce (Fig. 22). The confusion, however, to which the idea of a third ventricle gave rise influenced anatomy almost as late as the seventeenth century, and is illustrated in the anatomical figures of a late edition of Hans von Gersdorff (1556),[216] where the trachea is actually shown opening into the left ventricle (Fig. 23). It was Vesalius who took the first great step towards the discovery of the circulation of the blood, by firmly maintaining that the interventricular septum was solid and contained neither passages nor intermediate ventricle.[217]