The Fabric of the Human Body

Like many other Renaissance physicians and artists, Andreas Vesalius was driven by a desire to know the human body in all its parts and aspects.  An irresistible urge to dissect had mastered him even as a child, periodically leaving in its wake a succession of dismembered neighborhood dogs, cats, mice, and moles that had succumbed to his curiosity.  The son of a court apothecary, Vesalius was born in Brussels, and sent to Paris to study medicine.  Once there, however, he was greatly disappointed to find that his anatomy teachers were content to expound on Galen while poking around in the bodies of dead dogs.  Having reappeared at the beginning of the fourteenth century in Bologna, the practice of dissecting human bodies was spreading; more and more authorities began placing the corpses of executed criminals at the disposal of universities.  Searching for more rigorous training in anatomy, Vesalius left Paris and returned to Brussels, where, risking imprisonment, he stole a body from the gallows to acquire a complete human skeleton.  Next, Vesalius moved on to the University of Padua, where he received his medical degree in 1537 and was appointed professor of surgery and anatomy. Here, as elsewhere, anatomical demonstrations were highly ritualized events, with the professor seated above the corpse reading from a Galenic text, the surgeon dissecting, and the demonstrator pointing to the indicated parts of the body.  Not content with this division of labor, Vesalius took scalpel in hand, with the result that he soon proved many of Galen’s centuries-old observations to be false.  Because it was still unthinkable to dispute Galen’s claims, however, discrepancies between what was seen in the sixteenth-century corpse and what was written in the second-century text were ascribed to the "fact" that the human body had changed since antiquity.  Vesalius offered another explanation:  He was certain that Galen, in most cases, had dissected not human bodies but those of monkeys, goats, and pigs.  Setting out to portray a true picture of the human anatomy, Vesalius published the results of his anatomical work in De Humanis Corporis Fabrica, Libri Septem (1543), one of the most important of the early generation of printed books.  Containing 663 folio pages and more than three hundred illustrations by the painter Jan Stefan von Kalkar, the great treatise appeared in the same year that Copernicus redrew the anatomy of the heavens.


                To the Divine Charles the Fifth, Greatest and Most Invincible Emperor.

                    The preface of Andrew Vesalius to his book

                On the Fabric of the Human Body

Whenever various obstacles stand seriously in the way of the study of the arts and sciences and keep them from being learned accurately and applied advantageously in practice, Charles, Most Clement Caesar, I think a great deal of damage is done.  I think also that great harm is caused by too wide a separation of the disciplines which work toward the perfection of each individual art,...

Although once upon a time three schools of doctors existed, namely, the Logical, the Empirical and the Methodic, nevertheless the founders of these schools directed the aim of the art as a whole to the preservation of health and the elimination of diseases.  In short, they referred to this end all the things which the individual men in their schools deemed necessary to their art, and they were accustomed to make use of three aids.  Of these the first was a rational plan of diet; the second, all the uses of drugs; the third, surgery.  The last shows with particular aptness that medicine consists in the supplying of deficiencies and the removal of superfluities; and it ever stands ready for the cure of affections.  Time and use have shown that, as often as we engage in medical work, surgery is very helpful to the human race in its benefit to these affections.

This three-fold scheme of doctoring was equally familiar to the doctors of each sect.  The doctors themselves accommodated their own hands to curing in accordance with the nature of the affections; and they expended no less energy in training their hands than in the business of arranging the diet or of knowing and compounding drugs.  For instance, over and above his other books, the volumes which the divine Hippocrates wrote on the Role of the Doctor, on the Fractures of Bones, on the Dislocations of Joints, and evils of this type—the best written of all his works—show this clearly.  Indeed, Galen, that prince of medicine after Hippocrates, in addition to boasting frequently that the care of the Pergamene gladiators had been entrusted to him alone, and to being unwilling, although his years were heavy upon him, that the apes which were to be dissected by himself should be skinned by the labor of his servants, frequently impresses upon [his readers] how much he delighted in the craft of the hand, and how zealously he and the other doctors of Asia practiced it.

But no one of the ancients seems to have handed down to posterity with equal care the curing which is wrought by the hand and that which is accomplished by diet and medicines.  After the devastation of the Goths particularly, when all the sciences, which had previously been so flourishing and had been properly practiced, went to the dogs, the more elegant doctors at first in Italy in imitation of the ancient Romans began to be ashamed of working with their hands, and began to prescribe to their servants what operations they should perform upon the sick, and they merely stood alongside after the fashion of architects.  When, soon, others also began to refuse the inconveniences of those practicing true medicine, meanwhile subtracting nothing from their profit and honor, they promptly fell away from the standards of the early doctors.  They left the manner of cooking, and in fact the whole preparation, of the diet for the sick, to their attendants, and they left the composition of drugs to

the vendors of medicines, and surgery to the barbers. And so in the course of time the technique of curing was so wretchedly torn apart that the doctors, prostituting themselves under the names of "Physicians," appropriated to themselves simply the prescription of drugs and diets for unusual affections; but the rest of medicine they relegated to those whom they call "Chirugians" and deem as if they were servants. They shamefully reject that which is the principal and the most ancient branch of medicine, the one which rests primarily upon the observation of nature (if indeed it is anything else!).  Yet this branch of medicine even the kings in India practice today; and by the law of heredity in Persia they pass it all on to their children, as once the families of the Asclepiades did.  The Thracians, along with many other peoples cultivate and venerate it.  Although this art accomplishes absolutely nothing without the help of nature, but rather desires to aid her as she works to free herself from disease; when a part of the art, which the Romans in times past have proscribed from the state as if designed to deceive and destroy men, has been almost wholly neglected, the result is that the utility of the art as a whole is removed and destroyed.  To this primarily we owe the fact that this most sacred art is ridiculed, although many censures are normally cast at doctors anyway, since that part of the art which those educated in the liberal arts have shamefully allowed to be torn away is the part which permanently illuminates medicine with its especial glory.

When Homer, the fount of talents, affirms that the medical man is more preeminent than many, and when he and the other Greek poets celebrate Podalirius and Machaon, these sons of the divine Aesculapius are not lauded because they did away with a little fever which Nature alone cures more easily without the aid of a doctor than when the aid is applied or because they humored the palate of men in peculiar and lamentable affections.  They were celebrated because they were especially pre-eminent in the cure of haemorrhages, dislocations, fractures, contusions, wounds, and the other breaks in the continuity of the body.  They freed the most noble soldiers of Agamemnon from arrow points, javelins, and other evils of this sort which are principally caused by wars and which demand the careful attention of the doctor.

But, Most August Caesar, Charles, I have in no manner proposed to exalt any one instrument of medicine above the others, since the aforesaid three-fold method of help absolutely can not be disjoined and taken apart.  The whole method belongs to one workman.  To effect this synthesis properly, all the parts of medicine should be constituted and prepared equally so that all the individual elements can be put to use more advantageously, and each element in turn unites all together more perfectly. Now and then an extremely rare disease does turn up which does not immediately require the three-fold instrument of the safeguards.  And so a fitting plan of diet should be instituted, and finally something must be attempted by medicines and then by surgery.  Therefore tyros in the art should be encouraged in all the methods, and, if it please the gods, scorning the whisperings of the "physicians," they should apply their hands likewise to curing in whatever manner the nature of the art and reason really demand, as the Greeks did.  This they should do lest they turn mutilated medicine to the destruction of the common life of man.  And they must be encouraged in this

more diligently in proportion as we see today that the men who are more thoroughly grounded in the art abstain from surgery as from the plague.  They are afraid that they will be traduced by the fanatics of the medical profession before the unlettered populace as "barbers."  They also fear that afterwards they may not get half the profit, honor, or reputation in the eyes of either the unlearned mob or the leaders. This detestable opinion of many people in the first place keeps us from taking up the whole craft of healing; and we arrogate to ourselves only the cure of internal affections, we desire to be doctors only in a small way (to tell the truth for once!). The ensuing damage to mortals is great.  Indeed, when all the compounding of drugs was relegated to the pharmacists, the doctors in turn soon lost completely the knowledge of the simple drugs that were necessary to them.  The shops were filled with barbarous labels and crooked pharmacists.

Furthermore, this most perverse surrender of the instruments of healing to various artificers, has brought a much more execrable disaster and far more frightful calamity upon an outstanding part of natural philosophy.  To anatomical study, Hippocrates and Plato gave a high rank, since it embraces the study of man and since it correctly must be considered the solidest foundation of the medical art and the beginning of the constitution.  They did not doubt that it should be included in the first parts of medicine.  When this subject used to be practiced exclusively by the doctors, they stretched every nerve to master it.  But when they surrendered the surgical work to others and forgot their anatomical knowledge, it ultimately began to collapse.

As long as the doctors thought that only the curing of internal affections belonged to them, they considered that the mere knowledge of the viscera was abundantly sufficient.  They neglected the fabric of bones, muscles, nerves, veins and of the arteries which creep through the bones and muscles, as being of no concern of theirs.  When the whole business was committed to the barbers, not only did the true knowledge of the viscera disappear from among the doctors, but also their activity in dissecting straightway died.  This went so far that the doctors did not even attempt cutting; but those barbers, to whom the craft of surgery was delegated, were too unlearned to understand the writings of the professors of dissection.  It is far from the truth that this group of men preserved for us this most difficult art, transmitted manually to them; but it is true that this deplorable dispersion of the curative role brought a detestable procedure into our Gymnasiums, wherein some were accustomed to administer the cutting of the human body while others narrated the history of the parts.  The latter, indeed, from a lofty chair arrogantly cackle like jackdaws about things which they never have tried, but which they commit to memory from the books of others or which they place in written form before their eyes.  The former, however, are so unskilled in languages that they cannot explain the dissections to the spectators.  They merely chop up the things which are to be shown on the instructions of the physician, who, having never put his hand to cutting, simply steers the boat from the commentary—and not without arrogance. And thus all things are taught wrongly, and days go by in silly disputations.  Fewer facts are placed before the spectators in

that tumult than a butcher could teach a doctor in his meat market.  I shall not mention those schools where they hardly ever think of dissecting the structure of the human body, with the result that ancient medicine declined from its pristine glory years ago.

When at length in the great happiness of this age, which the gods have willed to be ruled by Your power, medicine had begun to revive along with all the studies, and had begun to lift up its head from the profoundest darkness so that it almost seems to have recovered its old splendor in some Academies; and since medicine now needs nothing more acutely than the dead knowledge of the parts of the human body, I decided to go to work on this book with whatever strength and brains I had, and with the encouragement of the example of so many distinguished men.  For fear that I alone might go slack at a time when all men are, with great success, essaying something for the sake of the common studies, or even for fear that I might fall away from the standards set by my progenitors, who were by no means obscure doctors, I thought that this branch of natural philosophy should be called back from the depths, so that, even if it should not be more complete among us than among the early doctors of dissection, nevertheless it should some day reach a point where one would not be ashamed to state that our method of dissection compares favorably with the ancient.  And one might say that nothing had been so broken down by time, and then so quickly restored, as anatomy.

But this ambition of mine would never have succeeded if, when I was studying medicine at Paris, I myself had not applied my hand to this business, and incidentally had the pleasure of being present at several public dissections put on by certain barbers for my colleagues and me when some viscera were superficially shown.  At that time, when we first saw the prosperous re-birth of medicine, anatomy was given rather perfunctory treatment there.  When some dissections of animals were being performed under the direction of that celebrated and most praiseworthy gentleman, Jacobus Sylvius, I was encouraged by colleagues and preceptors, although I had been trained only by my own efforts, to perform in public the third dissection at which I ever happened to be present—a dissection which dealt purely and simply with the viscera as was the custom there and I did it more thoroughly than was usual.  Moreover, when I next attacked a dissection, I attempted to show the muscles of the hand along with the more accurate dissection of the viscera.  For, aside from the eight muscles of the abdomen, badly mangled and in the wrong order, no one had ever shown a muscle to me, nor any bone, much less the succession of nerves, veins, and arteries.

... [At Padua] and at Bologna I performed dissections rather more often, and, having exploded the ridiculous custom of the schools, I taught in such a way that in anatomy we might want nothing which has been handed down to us by the ancients.

But indeed it should be noted that the sluggishness of the doctors has taken too little care that the writings of Eudemus, Herophilus, Marinus, Andrew, Lycus and the other leaders in dissection be preserved for us; not even a fragment of any page survives from the many illustrious authors, more than twenty of whom Galen mentions in his second commentary on Hippocrates’ book De natura humana. Why, hardly half of his own anatomical books have been saved from destruction! But those who have followed Galen, in which class I consider Oribasius, Theophilus, the Arabs, and all of our men however many I have chanced to read thus far (with your permission I would have written of these), if they handed down anything worth reading, they took it straight from Galen.  And, by heaven, to the man who is diligently dissecting they seem to have done nothing less than the dissection of the human body! And so, with their teeth set, the principal followers of Galen put their trust in some kind of talking, and relying upon the inertia of others in dissecting, they shamelessly abridge Galen into elaborate compendia.  They do not depart from him a hair’s breadth while they are following his sense; but to the front of their books they add writings of their own, stitched together completely from the opinions of Galen—and all of theirs is from him.  The whole lot of them have placed their faith in him, with the result that you cannot find a doctor who has thought that even the slightest slip has ever been detected in the anatomical volumes of Galen, much less could be found (now).

Meanwhile (especially since Galen corrects himself frequently, and in later works written when he became better informed he points out his own slips perpetrated in certain books, and teaches the contrary) it now becomes obvious to us from the reborn art of dissection, from diligent reading of the books of Galen, and from impeccable restoration in numerous places of (the text of) these books, that he himself never dissected the body of a man who had recently died.  Although the dried cadavers of men prepared, so to speak, for the inspections of the bones were available to him, he was misled by his apes, and he undeservedly censures the ancient doctors who had busied themselves with the dissection of men.  Nay, you may even find a great many things in his writings which he has not followed correctly in the apes; not to mention the fact that in the manifold and infinite difference between the organs of the human body and the body of apes, Galen noticed almost none, except in the fingers and in the bending of the knee.  This difference he doubtless would have omitted too, if it had not been obvious to him without the dissection of man.

But in the present work, I have in no wise set out to reprimand the false doctrines of Galen, easily the chief of the professors of dissection; and much less would I wish to be considered disloyal and too little respectful of authority toward that author of all good things right at the beginning of my work.  For I am not unaware of how much disturbance the doctors—far less than the adherents of Aristotle—raise when they observe that Galen deviated more than two hundred times from the correct description of the harmony, use, and function of the parts of man in treatment of anatomy alone, as I now exhibit it in the schools, while they examine sharply the dissected particles with the greatest zeal in defending him.  Although these men, led by the love of truth, gradually grow milder and put a little more trust in their rational faculties and their eyes—by no means ineffectual eyes and brains—than to the writings of Galen, they are now writing hither and thither to their friends about these truly paradoxical things which have neither been borrowed from the attempts of others or buttressed by congeries of authorities so sedulously and they have been urging their friends to learn some true anatomy so eagerly and amicably, that there is hope of its being fostered in all our Universities as it once was practiced at Alexandria.

In order that this may succeed under the happier auspices of the Muses, besides the works on this subject which I published elsewhere and which certain plagiarists,

thinking me far absent from Germany. sent forth as their own; I have now prepared afresh, and to the best of my ability, the history of the parts of the human body in seven books, arranged in the order in which in this city, at Bologna, and at Pisa I have been accustomed to treat it in the assembly of learned men.  I have done this with the specific idea that those who have attended the dissector [at work] will have commentaries of the demonstrated facts, and will show anatomy to others with lighter work; although the [commentaries] will not be entirely useless to those to whom direct observation is denied, since of each particle of the human body the site, form, substance, connection to other parts, use, function, and very many things of this sort which we have been accustomed to turn up during dissections in the nature of the parts, together with the technique of dissecting both dead and live men, are pursued at adequate length.  The books contain pictures of all the parts inserted into the context of the narrative, so that the dissected body is placed, so to speak, before the eyes of those studying the works of nature.

Truly, there is no one who does not find out in geometry and in the other mathematical disciplines how much pictures help in the understanding of them, and place the matter before the eyes more clearly, even though the text itself is very explicit.  But however that may be, in the whole of this work I have striven with the purpose that, in an exceedingly recondite and no less arduous business, I should help as many as possible and that I should treat as truly and completely as possible the history of the fabric of the human body, a fabric not built of ten or twelve parts, as it appears to the casual observer, but of several thousand diverse parts; and finally that I might bring to the candidates in medicine a grist not to be scorned for the understanding of the books of Galen in this field which, among his other monuments, require especially the help of a preceptor.

But in the meanwhile, it is perfectly clear to me that my attempt will have all too little authority because I have not yet passed the twenty-eighth year of my life; it is equally clear that, because of the numerous indications of the false dogmas of Galen, it will be exceedingly unsafe from the attacks of the conservatives, who, as with us in the Italian schools, have sedulously avoided anatomy, and who, being old men, will be consumed with envy because of the correct discoveries of the young, and will be ashamed of having been blind thus far, along with the other followers of Galen.

BALDASAR HESELER (ca. 1508-1567)

            Andreas Vesalius’ First

            Public Anatomy at Bologna, 1540:

        An Eyewitness Report

Born in Liegnitz, in Silesia, Baldasar Heseler came from a German family of public officials and businessmen. Before undertaking the study of medicine, Heseler completed a degree in theology under Martin Luther at the University of Wittenberg. From there, he went to the University of Leipzig and, like many of his fellow students, rounded out his medical education at the University of Bologna.  After graduating in 1540, Heseler returned to Silesia, becoming a physician of high repute in the town of Breslau.  Although thousands of students attended Vesalius’s presentations, Heseler’s account survives as the only set of notes actually taken during these demonstrations.  Also included in Heseler’s text are Matthaeus Curtius’s commentaries on the Anatomy of Mondino (Mundinus in Latin); these always preceded the demonstrations of Vesalius, who adroitly used the text of the body to disprove the text of Mondino.


The anatomy of our subject was arranged in the place where they use to elect the Rector medicorum (Head of the Medical Faculty); a table on which the subject was laid, was conveniently and well installed with four steps of benches in a circle, so that nearly 200 persons could see the anatomy.  However, nobody was allowed to enter before the anatomists, and after them, those who had paid 20 sol[di].  More than 150 students were present and D. Curtius, Erigius, and many other doctors, followers of Curtius.  At last, D. Andreas Vesalius arrived, and many candles were lighted, so that we all should see, etc.

Then D. Vesalius began:  Domini, you know how doctors, both ancient and modem, use to divide the human body.  The Egyptians and the Arabs begin with the trunk and the extremities, but Galen, whom also Mundinus has followed, begins with the three venters.  But leaving these questions (because Curtius requested him to demonstrate what [Curtius] had lectured) we shall proceed to our anatomy.  And there was the body cut up and prepared beforehand, already shaved, washed and cleaned.  He began with the outer skin, to which the inner one adhered, that is rightly called the skin, cutis, the outer one being better named hide.  And, he said, these two cannot well be separated, because the inner one is too subtle and really spermatic, which when ruptured or cut cannot be healed.  And he proved the difference between these

two in the following way: with a candle he burnt the outer skin which is called corium, and showed us how it turned into blisters, while the inner skin, however, did not blister because it was more fleshy and fleshlike than the outer one.  The inner skin was whitish, having the form of the sperma, out of which it has its origin. Because, he said, the complexion always takes the form and nature of the components, out of which they originate, as the skin, in otherwise the same conditions, in colour take and appropriate the nature of its humours.  Then there was the fat adhering to the fleshy layer beneath the skin, that had been separated from it with a razor, and he declared that the fat which moistened the skin, coagulated because of the coldness of the skin. In this membrane or layer he demonstrated to us the black ends of the veins and the openings of the nerves, the veins for the nourishment of both kinds of skin and the nerves for the feeling of the inner skin.  This he showed us in the left side.  In the right side, again, he had not removed this layer.  In this way, he said, the butchers strip the carcasses.  At last he came to the anatomy of the muscles, which, extremely skilled in dissecting as he was, he had dissected with the utmost diligence so that the substance, the size, the position, the beginning and the end of each one of them could be clearly seen.


He had stripped off the skin of the entire inner side of the arm to the tips of the nails of the hand.  And before he demonstrated the dissection [of the muscles], their position etc., it is necessary, he said, for you beforehand to know the anatomy of the bones; for from the extremities of them all the muscles have their origin beginning at the head with a sinew and ending tied [to the bones] at their caudae with the tendons or cordac.  Accordingly he demonstrated to us in the promised anatomy of the bones, how the muscles begin at the heads of the bones and how they end with their tendons at the hands and at each of the joints of each finger. Thereafter, he enumerated to us the muscles of the interior side of the arm, which tend towards our head, and he showed by dissection how the muscles with a thin sinew begin at the head of the bones of the arm and how after a long course they end in the hand and the joints of the fingers, how the muscles in double layers are situated one over the other, always four over four, and how the lower ones tend to the first joints, the upper ones to the second and third joints, and always pass through the first ones.  Certainly this was very beautiful to see.  And he showed us how these sinews at the same time were covered by a special membrane, and he separated them from each other and followed them to the joints of the fingers. About this he said: please, read Galen, De usu partium, I and II, De anatomicis administrationibus, I, and about the muscles of the organs.  Tomorrow we shall see the anatomy of the muscles of the exterior part of the forearm or the cubitus.

                             THE ELEVENTH DEMONSTRATION

                    The Anatomy of the ‘Didimi’

Mundinus goes on to the spermatic vessels of the female, to the uterus etc. but all that we shall pass, as we now have no female body.  But we shall explain the anatomy of the spermatic vessels of the male and first the anatomy of the testicles. . . . Galen says that the organs of procreation are the same in the male and in the female, only that in the female all is reversed to the male, in whom that which is inside in the female is outside.  And again in the male all is contrary to the female. For if you turn the scrotum, the testicles and the penis inside out you will also have all the genital organs of the female, like they are in the male. (Yet the penis of the male is more solid, the neck of the uterus of the female more excavated and concave and much more extendable in time of coitus and parturition.)  Vice versa, if you turn inside out the genital organs of the female, you will have all the organs of the male.  Thus, they differ only by being reversed.  The reason of this reversion in the female is that they have all their genital organs inside, and that is, I maintain, owing to their lack of natural warmth.  Therefore in women these organs have stayed inside.  This results in three great advantages in woman.  One is that their genital organs are inside in order to receive man’s seed.  The second reason is that women increase the superfluous blood and humidities, which they have attracted, and that thus they overflow with superfluous blood, namely for the production and nourishment of the foetus.  This is why not-pregnant women menstruate naturally each month, but when they become pregnant, the fluids are retained for the said purpose, namely conserved for the nourishment of the foetus.  The third reason is that they cannot conceive by their own seed without the intercourse of the male.  For [the seed of the male] is required, because it is hotter and more perfect, but that of the female colder.


Because our next subject was hanged this morning (there were two of them) during Curtius’ lecture and they were still hanging, as I myself saw, the students in the meantime had killed a pregnant bitch, which was the fourth dog.  Hence, this morning D. Vesalius demonstrated the anatomy of the uterus and of the embryos contained in it, the puppies.  He showed how the arteries and the veins outside the uterus converging ran to the umbilicus of each foetus, and there was always an interval or an interspace between them at each foetus.  And in this dog there were seven puppies.  Thereafter he opened the substance of the uterus, which was membranous, sinewy, elastic and rather soft.  Thereafter a second membrane appeared where the umbilical vein and artery ran together.

Then there was another sack in which the sweat of the foetuses was received.  The fourth and last was that in which the urine of the foetuses was contained.  When we had seen this, he dissected two puppies showing us in them the composition of the umbilicus, namely how two veins ran to the liver conveying the nourishment, and two arteries to the heart conveying spirits and warmth.  And there was one white duct that tended to the side of the bladder, and it was strongly connected to and entered the bladder, and through this duct the urine was transmitted into the fourth and last sack mentioned before.  And thus the anatomy of the pregnant [dog] and the foetuses is completed.


When the lecture of Curtius was finished, Vesalius, who had been present and heard the refutation of his arguments, asked Curtius to accompany him to the anatomy. For he wanted to show him that his theory was quite true.  Therefore he brought Curtius to our two bodies.  Now, he said, excellentissime Domine, here we have our bodies.  We shall see whether I have made an error.  Now we want to look at this and we should in the meantime leave Galen, for I acknowledge that I have said, if it is permissible to say so, that here Galen is in the wrong, because he did not know the position of the vein without pair in the human body, which is the same today just as it was in his time.  Curtius answered smiling, for Vesalius, choleric as he was, was very excited:  No, he said, Domine, we must not leave Galen, because he always well understood everything, and, consequently, we also follow him.  Do you know how to interpret Hippocrates better than Galen did?  Vesalius answered:  I do not say so, but I show you here in these bodies the vein without pair, how it nourishes all the lower ribs, except the two upper ones, in which there is no pleurisy.  For always here—he knocked with his hands against the middle of the chest—occurs inflammation and pleurisy, not at the two upper ribs.  Consequently, as this vein also is distant from the heart, as you see, by three fingers’ breadth, it will always in pleurisy and all morbus lateralis (lateral illness) be better to bleed from this vein only; or it ought to be no difference from what part the bleeding is done, because the ribs are nourished exclusively by this vein.  Curtius replied:  I am no anatomist, but there can be also other veins nourishing the ribs and the muscles besides these.  Where, please, Vesalius said, show them to me.  Curtius said:  Do you want to deny the ducts of Nature?  Oh!, Vesalius said, you want to talk about things not visible and concealed. I, again, talk about what is visible.  Curtius answered:  Indeed, I always deal with what is most obvious. Sir, you do not well understand Hippocrates and Galen concerning this.  Vesalius replied:  It is quite true, because I am not so old a man as you are.  Thus, with much quarrel and scoffing they attacked each other, and in the meantime they accomplished nothing. Vesalius said:  D. Doctor, I beg Your Excellency not to think me so unskilled that I do not know and understand this.  Smiling Curtius said:  Sir, I did not say so, for I have said that you are excellent, but I have rejected the wrong explanation of Hippocrates implying that Galen should have erred in this.  Vesalius replied:  I acknowledge that I have said that Galen has erred in this, and this is evident here in these bodies, as also many other mistakes of his.  When Curtius asked Vesalius not to be angry with him, Vesalius said:  not at all, Domine.  And thus Curtius left.