Transplanting Animal Organs


Transplanting Animal Organs


IN May, seven years ago, an important meeting took place at the Arlington Hotel in Washington. On that occasion, at the invitation of Mr. John D. Rockefeller, five of the most distinguished medical men in the United States met to discuss the foundation of an institution for scientific medical research. Until this meeting no institution devoted exclusively to this subject existed in this country. In experimental medicine Europe had left the United States far behind. The Pasteur Institute in France, the Lister Institute in London, the Imperial Health Office in Berlin, had taken the leadership for more than twenty years. Even Russia, with its great Imperial Institute at St. Petersburg, and Japan, with its Institute for Infectious Diseases at Tokio, had made many important additions to medical knowledge.

American medical men had long regarded this as a serious national reproach, especially as nearly all the great discoveries of the last forty years have been the result of laboratory experimentation. It was not a medical man at all, but an experimental chemist, Louis Pasteur, who, in demonstrating the relations existing between living micro-organisms and contagious diseases, became the real father of modern medicine. Pasteur not only achieved great immediate practical results; he also created a method. The lonely little house at Alais, where he spent five years in investigating the diseases of silkworms, was the precursor of the laboratories now located in all the great capitals of the world. Following Pasteur’s example, medical men have now learned to use their eyes, to take nothing for granted, to pay less deference to accepted authorities, and to form conclusions of their own, based upon carefully observed facts.

The outcome of the Washington conference referred to above was the Rockefeller Institute for medical research. Its mission is to apply, in the United States, the methods of investigation which, in other countries, have made such useful contributions to civilization. Starting in a small way, with no building of its own, and a fund of only $200,000, it now has a large structure at Sixty-sixth Street and Avenue A, New York, and resources of nearly $4,000,000. Its management is supervised by seven directors, all of them men of scientific eminence. Dr. William H. Welch, who, as head of the medical department of Johns Hopkins University, has done so much to create a new spirit in medical science in this country, is its president; and one of his most successful pupils and associates, Dr. Simon Flexner, who has already done much invaluable work in bacteriology, is the director of its laboratory. The other members of the Board are Dr. L. Emmett Holt, a man with a European reputation as an authority on the diseases of children; Dr. T. Mitchell Prudden, who has created the department of pathology at Columbia University; Dr. Herman M. Biggs, who, in spite of every discouragement and disadvantage, has made the New York Health Department a model municipal agency in fighting disease; Dr. Theobald Smith, of Harvard University, whose demonstration of the fact that Texas cattle fever is caused by an animal parasite carried by the cattle tick in large measure paved the way for the discovery of the relation between malaria and a certain species of mosquito; and Dr. Christian A. Herter, well known as an authority on nervous diseases and chemical pathology.

The laboratory building of the Rockefeller Institute stands upon a rocky bluff facing on the west a densely packed tenement population —one of the most prolific breeding-places of the diseases whose secrets the investigators seek to penetrate— and, on the east, Blackwell’s Island, a centreing point for much of that misery and vice in the making of which disease plays no inconsiderable part. The Institution is modern, not only in its scientific atmosphere, but in a fine type of idealism. It is the headquarters of fifteen or twenty enthusiasts who have isolated themselves, in nearly all cases as young men, and given all their time to this work of research. As Edmond About said of Pasteur, they are seeking, not to cure individuals, but to cure humanity. If they make any important discovery, they give it freely to mankind with no reward except the recognition and satisfaction of having done something worth while.

In practically every department— surgery, pathology, bacteriology, chemistry, and physiology — excellent results have already been obtained. In this and subsequent articles will be described some of the most important work already accomplished.

Among the most far-reaching of these experiments are those conducted by Dr. Alexis Carrel in the transplantation of animal organs. For the first time in medical history Dr. Carrel has demonstrated the important fact that the kidney of one animal can be transplanted into another animal and perform, for a considerable period, its normal functions. He has also proved that the leg of one dog can be successfully joined and made to grow upon the leg of another. These experiments are not mere surgical curiosities; like all the work of the Institute, they are undertaken for the purpose of accomplishing certain definite results.

Great progress has been made in the last thirty-five years in the prevention and cure of contagious diseases—diseases, that is, of bacterial origin. But the numerous disorders or the kidney, liver, spleen, and other important viscera, which, in the opinion of most pathologists, are not caused by bacteria, baffle medical men almost as much to-day as they did fifty years ago. The ravages of typhoid, diphtheria, and tuberculosis have been greatly checked; Bright’s disease is still regarded by both the popular and professional mind, as incurable. For generations medical men have dreamed of treating these chronic affections in a direct and obvious way—that is, by removing sick organs and substituting new ones. If you have a bad kidney or a bad liver, the most satisfactory procedure, were it surgically possible, would be simply to get a new one. There are likewise many diseases of the arteries and veins, the most satisfactory treatment of which would be the transplantation of healthy vessels in place of those diseased.

Another similar idea is the replacement of useless legs and arms with the more serviceable limbs of other people. In the Golden Legend of Jacobus de Voragine the story is told of a pious saint who received, as an especial favor from heaven, the healthy leg of a negro in place of his own diseased member. As a result of experiments conducted in the last five years by Dr. Carrel, it seems possible that what was the miracle of an age of faith may become the reality of an age of science.

Dr. Carrel, an unassuming young Frenchman, is himself a fine example of the idealistic spirit dominant in modern science. His skill as a surgeon would easily bring him a very large income; he prefers, however, the isolated work of the Institute. From the first Dr. Carrel has been a man with a fixed idea. As a medical student at the University of Lyons he conceived the possibility of utilizing healthy animal organs and vessels to do the work of those which had become diseased. Naturally, these ideas, coming from an enthusiastic young man, inspired little confidence. In spite of the great discoveries of modern French science, new ideas gain ground slowly in France. In Lyons Dr. Carrel did some interesting work; about 1905, however, hampered by the lack of proper working facilities at home, and convinced that his ideas would have a favorable reception in this country, he came to the United States. He became associated with the University of Chicago, on the staff of its distinguished professor of physiology, Dr. G. N. Stewart. Here, among other important operations, he succeeded in transplanting the kidney of a dog from its natural locating in the lumbar region to the dog’s neck. In 1906, his success in this direction led to an invitation to join the staff of the Institute.

Before the transplantation of animal organs is possible, a large amount of preliminary work has to be done on the veins and arteries. The aorta, the great trunk artery, and the vena cava, the great trunk lit vein, lead directly from the heart down into the abdominal cavity, and with certain important branches, connect with and largely hold in place the large abdominal organs. In order to remove the kidney, the liver, or the spleen, therefore, it is first necessary to cut these great blood-vessels. Medical men had long regarded the vascular system as sacred, and to cut the aorta, in the opinion of most surgeons, would inevitably cause death. No one had yet succeeded in uniting severed blood-vessels by simple suture; in certain cases, by the use of magnesium tubes and other contrivances, this latter operation had been performed, but no experimentalist, before Carrel, had developed a method that was simple and almost invariably sure.

An examination of an animal artery sufficiently explains why surgeons should approach it with trepidation. Thin as are its walls, it is an extremely complicated structure. Viewed under the microscope, it consists of three distinct coats or layers, each lying closely upon the other, but each absolutely distinct from its next neighbor. Each coat has its own independent part to play in the world; one provides the elasticity that makes pulsation possible, another furnishes muscular power, while the innermost section, called the intima, consists of a smooth, free surface, for immediate contact with the flowing blood. To cut these several layers and make them grow together again would in itself require great skill in surgical carpentry; what rendered it all but impossible was the blood itself. We are all fairly familiar with the common phenomenon known to surgeons as a thrombus, and to most people as a blood clot. Blood, when once freed from the artery, coagulates—forms into a sticky, glutinous substance. If a clot of any appreciable size gets into the circulation, it may land in the brain or some other vital part and cause death. It was the fear of a disaster of this kind that made surgeons hesitate to disturb a healthy artery.

The discovery made by Dr. Carrel was, like most discoveries, entirely simple and elementary. He found that no elaborate contrivance, such as a magnesium tube, was necessary; that, if proper skill and proper asepsis were used, a severed artery could be simply sutured with a very small needle and very fine silk. He discovered that, in joining the severed ends, he could practically disregard the different layers of which the vessel is composed, with the exception of the innermost one. If the intima of one severed end were perfectly joined to the intima of the other end, the remaining coats would practically take care of themselves.

The whole technique developed was beautiful in its minuteness and its simplicity. It would almost require a microscope to follow it in all its details. The usual way of stopping circulation, preliminary to a surgical operation, is by the use of metal clamps, which, pinching the walls of the vessel together, check the flow of blood. Dr. Carrel found that the metal clamps wounded the artery and frequently brought about the dreaded coagulations. He therefore stopped the circulation by winding around the artery a narrow strip of linen, and pulling this tight with surgical forceps. He then cut the artery with small and extremely sharp scissors. Snipping it thus in two places, he could remove a segment of any desired length. This he carefully washed, inside and out, with a cleansing solution, in order to remove all the blood and any extraneous matter that might possibly have slipped in, and then, to protect it against new encroachments, thoroughly coated it with vaseline.

In securing this in place, either in the same animal or another, the danger of wounding the tissue, and thereby producing blood clots, again constantly threatened. Even in the little holes made by the tiny needles, diminutive coagulations might form, containing in themselves the chance of serious disturbance. To protect these holes, Dr. Carrel used another simple device; he thoroughly coated the silk thread with vaseline. As the silk passed through the walls of the artery, the vaseline was scraped off and left as a protective coating in the holes; it quickly healed the microscopic wounds and prevented thrombosis. By this operation, Dr. Carrel, or any surgeon equally skilful, could do what has always been regarded as impossible—cut the aorta of a man, at a short distance from the heart, and sew it together again. Indeed, the aorta is more easily handled than other arteries, because it is so large and tough. In cutting the aorta the circulation would be entirely stopped in the lower part of the body, and thrown into the upper; but, for the hour or less that such an operation would take, this could be done.

On animals, by using this method, Dr. Carrel has performed many important transplantations. He has taken the aorta from one dog and sewed it into the aorta of another. He has transplanted sections of the arteries of dogs and cats with ease. The animals, being under a heavy anesthetic, suffer absolutely no pain, either during or after the operations. The wounds rapidly heal; no blood clots result; and the subjects are soon capering about, unconscious of the fact that they are using each other’s blood-vessels.

More interesting still, Dr. Carrel has found that, under favorable circumstances, he can make veins do the work of arteries and arteries do the work of veins. It is assumed that the average reader understands the difference between these two kinds of blood-vessels — that an artery is the channel through which the red blood is rapidly pumped through the body, carrying nourishment and life; and a vein the channel through which this same blood, blue and vitiated, sluggishly finds its way back to the heart. Since arteries have much harder work to do than the veins, nature has made them thicker and more elastic; and physicians had hardly conceived it possible that they could be interchanged. Dr. Carrel, however, has cut out a section of the aorta of a dog, and replaced it with an equally long section of the vena cava—the largest vein—of another dog. Similarly, he has replaced part of the carotid artery—the main artery of the neck— with a corresponding part of the jugular vein. He has found that nature, when this violent change in its organization takes place, goes patiently to work to readjust matters; veins transplanted upon arteries grow thicker and elastic, so that they may do the work of arteries; arteries transplanted upon veins lose much of their elasticity and strength.

If these operations come to be performed on man, the possibility of using veins for arteries will be of the greatest importance. The difficulty of repairing human arteries by transplantation is the practical one of getting the material. People who have healthy blood-vessels do not care to present them to their suffering brothers. We need all the arteries we have—not a section can be permanently removed without disastrous results. The body is filled with superfluous veins, however, and we could easily find, in our own persons, a segment of vein to take the place of a diseased artery.

At present, however, this interchange is not always successful; many times a vein, in attempting to readjust itself to its new functions, overdoes the matter; its walls become so hard and thick that little space, sometimes no space at all, is left as a channel for the blood. A situation results something like arterio-sclerosis—that hardening of the arteries that works such havoc among old people. This fact has led Dr. Carrel into a new field of experimentation: a testing of the possibility of using the vessels of an animal of one species in an animal of another. One of the recent discoveries of medical science is the fact that the blood serum of one species acts as a poison upon the tissue of another. But to this rule occasional exceptions have been found. If the different species are somewhat closely related, if the origin of one in zoologic time is not too far removed from that of the other, successful grafts may sometimes be made. You cannot graft the skin of a mouse upon a lizard, because these two animals are only remotely related; you would probably succeed better in transplanting tissue from a guinea pig to a rabbit, or from a cat to a dog, or possibly from an anthropoid ape to a man, for these species are supposed to be rather closely allied. As far as blood-vessels are concerned, Dr. Carrel has discovered that the arteries of one species frequently preserve a normal existence in the body of another species. He now has a living healthy cat which contentedly uses, as part of its circulatory system, the carotid artery of a dog. One of his associates in Chicago, Dr. C. C. Guthrie, has successfully inserted in a dog the arteries of a rabbit and a cat. Whether the arteries of a dog can survive and do their work in a human body has not yet been demonstrated, but it is known that the contrary of this principle is true. Dr. Carrel now has a dog, part of whose aorta is composed of a section of artery taken from a man’s knee. The animal’s pulse is entirely normal; it is, indeed, in perfect health.

To the unscientific citizen it is something of a surprise to learn that large parts of the body are alive and useful after the phenomenon popularly known as death has taken place. Few of us suspect, for example, that our kidneys and hearts, after we have died ourselves, can in most cases, be resuscitated, and that it by some surgical miracle, could be transplanted into another body, they would quickly resume their functions. This, however, is a well demonstrated medical fact. The human heart has been removed from the body more than thirty hours after death and made to beat again. Dr. Carrel himself has taken the heart from one dog and inserted it in the neck of another, connecting the carotid artery with the aorta of the new heart, and the vena cava with its jugular vein. In a few moments the live dog had two hearts rhythmically beating, one recording a pulse of 88 and the other of 100.

Science has yet framed no precise definition of death. The human body teems and quivers with life, only a small part of which becomes a part of individual consciousness. The healthy man hardly realizes the numerous and complex activities of his internal organs. The alimentary canal is the abiding-place of millions of micro-organisms, the activities of which only occasionally influence our daily life. Bodily tissue everywhere is constantly breaking down and constantly building up; and yet it is only in the last few years that even science has begun to understand the beautiful chemical reactions involved in the process.

Perhaps the white corpuscles of the blood—the leucocytes—furnish the most perfect illustration of this life which is in and yet is not of us. Upon their activity a whole new science, that of phacocytosis, has been founded. Metchnikoff has described how these white corpuscles, among their numerous other activities are constantly escaping from the blood and pursuing and devouring invading microbes and thus protecting the body from disease. In the intestines a battle is constantly taking place between these white corpuscles and destructive bacteria, in which the combatants on both sides, number millions and billions; yet, although we are ourselves the battleground, we know nothing of it. These same leucocytes, as has been discovered by Dr. Eugene L. Opie, of the Rockefeller staff, seem almost to have an immortality of their own. They can be removed from the body, ground into a fine grayish white powder, and placed away for months in glass tubes; and then, when reintroduced into the tissues, immediately resume some of their old activities. Death, as popularly understood, is a loss of personality; the eternal separation of human consciousness from inert mortal clay. Theology teaches that the spirit lives forever—that only the body perisheth; science, on the other hand, while it says nothing about the eternal life of the spirit, teaches the immortality of the body. It may change its form, but it will never pass into nothingness.

Even after death the important organs, in their existing form, live for a certain time. The heart, as has already been said, in specific cases, has resisted devitalization for more than a day; the kidneys also can probably survive for a considerable period. The shortest-lived organ is probably the brain; this seldom lasts more than fifteen minutes after the passing of the spirit. "But there are certain artificial ways in which animal tissue can be kept alive for days and weeks, perhaps for months. Nature thus gives the scientist a short breathing-space—the lapse between death as it affects personality, and death as it affects the vitality of the cell. If, in that period, the essential bodily organs are removed, they can be preserved for a long time.

Two forces, after death, begin their destructive work upon animal tissue. The first is microbial; untold millions of bacteria pounce upon the body and cause the common phenomenon of putrefaction. The other force is a comparatively recent discovery of science: the far more subtle and mysterious disintegration known as autolysis. This is a Greek word which may be freely translated as self-digestion. Food taken into the stomach is converted into certain substances—proteids, sugar, and starch—by digestive ferments or enzymes, especially pepsin and trypsin. It is of these proteids, sugar, and starch that the body is composed. After death, tissue begins to disintegrate into the substances of which it was originally formed; human flesh undergoes almost the same chemical change that food undergoes in the body; in other words, it is digested. In this case the digestion, so far as science can discover, takes place without the action of specific digestive ferments. The tissues literally chew themselves to pieces; the cells possess some inherent power which they use for their own destruction. If a human body were absolutely sterilized and thus freed from the attacks of bacteria, its dissolution, under this process of autolysis, would still go on; after a certain period —and not a very long one —nothing would be left but a limpid fluid, and this, if resolved chemically, would leave a clear, white, powdery substance—largely the same proteids and sugar of which the living body is composed. The mortal cycle is thus complete; science rephrases the Biblical injunction; proteids we are, and unto proteids we shall return. Imperial Caesar, dead and turned to clay, might not stop a hole to keep the wind away; a considerable part of him, however, could be served up as very palatable table sugar.

Thus, in order to preserve an organ after death, it must be protected against these two destructive forces. Against putrefaction simple sterilization suffices. An artery, for example, thoroughly disinfected, placed in an ordinary culture tube, and then closed to the access of all bacteria, will not putrefy. Under ordinary circumstances, however, it will undergo autolytic disintegration. Complete desiccation will preserve it against this later process. Autolysis does not take place except in the presence of water; this explains why Egyptian mummies, which were thoroughly dried before being placed away in the tomb, have resisted for thirty centuries the autolytic ferment. Normal blood serum is another substance which inhibits, to a considerable degree, autolytic degeneration. Cold, while it does not entirely check the process, makes it exceedingly slow. It is upon refrigeration that Dr. Carrel has thus far chiefly depended for preserving arteries. In order to prevent putrefaction, he places them in sterilized culture tubes, and then he puts away the tubes in large ice-chests, which maintain a temperature just above the freezing-point. Here they live in a condition of suspended animation. Dry and shriveled as they appear, they are still living tissue; and, although the animals from which they have been taken have long since gone to their final rest, these fragments, if placed in a new living host, once more take up the thread of existence. That the arteries could be removed from a man recently dead and have their vitality and usefulness preserved in this same fashion, is absolutely certain.

Important as is the bearing of these experiments with blood-vessels upon the ultimate problem— the transplantation of the visceral organs and of limbs—they have many immediate practical applications in themselves.

Dr. Carrel’s work on arteries has given the world its first complete and satisfactory method of transfusing blood. Operations by which the blood of one person is injected into the circulatory system of another are not particularly new. For patients suffering from anaemia— that is, an insufficiency of healthy nutritive blood—the obvious treatment is the infusion of the precious fluid of a more fortunate person. The first successful operation of this kind was performed more than two hundred years ago. The operation, however, has never been reduced to an exact science, because of certain almost insurmountable difficulties. The great problem of transfusion has always been to get the blood from one person to another without the formation of blood clots. Hitherto, the most successful plan has been to pour the blood into a receptacle and to beat it, much as a cook beats an egg; this process separates from the blood the fibrin, the substance about which the clots are formed. At best this is a clumsy method, and the results have been far from satisfactory. Now, thanks to Dr. Carrel’s work, transfusion, if undertaken by competent men, can be systematically performed. Taking an artery from the full-blooded subject, he sutures one end upon an artery of the anaemic; and, by establishing a perfect circulation, the arterial systems of two people for a time become almost as one.

On a certain occasion Dr. Carrel demonstrated the value of this operation. A brother physician called him out one night to perform a transfusion upon his own infant, which was only five days old. The child was almost dead from lack of blood; indeed, to the superficial observer, life was already extinct. Dr. Carrel took the radial artery of the child’s father and sutured it to the popliteal vein of the child. In a few minutes important changes followed; the child’s ears became pink, its lips turned from blue to red, and soon the whole body became suffused with a healthy pink glow. Promptly the child began crying for food, and it is now as robust a baby as one could wish.

This operation and similar operations have become a regular feature of surgical practice, both in this country and in Europe. Only a short time ago a child three years old was admitted to the Babies’ Hospital of New York suffering from a large tumor of the kidney, but in such bad condition that under ordinary circumstances operation was out of the question and it seemed as if the child must surely die. After transfusion with the blood of the father the child improved so markedly that it was considered safe to proceed with the operation. It was successfully performed, the child made an excellent recovery, and is now well and strong. This is only one illustration of the numerous applications of this new principle in surgery.

Dr. Carrel’s work on the arteries also points to a new treatment for aneurisms. An aneurism is caused by the accumulation of blood in an artery; at the diseased part a sac is formed, sometimes very large, and, unless it is checked, it will burst, and the blood, flowing into the surrounding tissue, causes death from hemorrhage. Many methods of treating aneurisms have been evolved, all of them unsatisfactory. Hitherto the surgical removal of the aneurism usually included the destruction of part of an artery. This meant that a particular section of the body, not receiving its usual allotment of blood and nourishment, would develop gangrene. According to Dr. Carrel, ideal treatment would be to cut out that section of the artery containing the aneurism, and replace it with a segment of a healthy artery from some other source. Up to the present time this operation has not been attempted, because the idea is new and because of the practical difficulty of obtaining extraneous human blood-vessels.

Another interesting application of the new blood-vessel surgery would be its use for drainage purposes. The new method of suture could probably be used to establish a kind of conduit in the body, which might carry away the watery accretions that accumulate in certain well-known diseases. Hydrocephalus is a not uncommon affection among children; it is an accumulation of fluid in the cavities of the brain, and leads to an abnormal and sometimes monstrous development of the skull, and frequently to imbecility. A possibility suggested by Dr. Carrel would be to take a segment of vein, suture one end into the dura-mater, and thus obtain a connection with the fluid in the brain; the other end could then be attached to the jugular vein. The water in the brain would thus flow by gravity into the circulation. An experiment of this nature has been successfully tried for dropsy. Among the natives of Africa the swelling of the abdomen from dropsy is a common phenomenon. A well-known French surgeon, operating in a chronic case, inserted a vein into the abdominal peritoneum, thus obtaining immediate connection with the water, and caused it to flow into the venous system of the leg. The swelling in this case disappeared. In regular practice “tapping” for dropsy is common; this system of drainage supplies a permanent “tapping,” for as soon as the water forms, it passes into the veins. In the circulatory system it causes no damage, because the hydrocephalic and the dropsical fluids are about the same thing as blood plasma itself. Any impurities that enter the blood in this way are excreted precisely as are other impurities.

Important as are these transplantations of blood-vessels, however, they are merely preliminary to the far greater problem of transplanting organs.

In these operations every precaution is taken to prevent the animals from suffering needless pain. In the large majority of cases they undergo absolutely no distress, and in no instances does their physical discomfiture become acute. A cat operated upon by Dr. Carrel does not suffer even as much as would a human being who should be subjected to the same experiment. That long period of anticipation which, to a human subject, is probably the severest part of the ordeal, an animal obviously does not experience at all. As a matter of fact, because of the great precautions taken in the use of anesthetics, the animals operated upon are absolutely unconscious of the experiment.

The cats that are the subjects of Dr. Carrel’s operations are of the homeless, marauding kind. The army of human waifs in a great city arouses everywhere interest and sympathy; the even greater number of animal waifs attracts much less attention. It is the miserable hunted vagrant, half-starved and cringing, picking up a spare living on the refuse of ash-cans, that, occasionally finding its way into the Rockefeller Institute, furnishes the material for these experiments. There it finds, not a torture chamber, but a really comfortable home. It is cared for by men expert in handling animals, and has plenty of good, wholesome food, and a warm, comfortable bed. While the animal lives, every possible precaution is taken to assure its comfort; and, if its life is ultimately sacrificed in the interest of medical science, it goes down to an easeful death with chloroform. Had it not joined the animal colony at the Institute, it would have starved to death or been suffocated ultimately at the public pound.

The question still remains as to what is the net practical outcome of these experiments. Dr. Carrel, though enthusiastic in his work, is extremely conservative in estimating the importance of results already accomplished; he is working toward a definite goal, and he would be the last to assert that he had yet reached it. This line of experimentation is practically new and presents possibilities of such startling importance that the surgeon must carefully feel his way. It is evident, from what has already been said, that these operations indicate many lines of investigation that, when brought to completion, may revolutionize surgery and, perhaps, lead to the successful treatment of certain chronic disorders. Dr. Carrel’s work clearly divides itself into two parts —one in which success has already been obtained; the other one in which important discoveries have been made and startling operations performed, which, in the opinion of conservative men, clearly indicate more remarkable results in the future.

In suturing blood-vessels, in transplanting them from one animal to another, and in preserving them before such transplantation in cold storage for weeks in good condition, Dr. Carrel has already achieved complete success. In the transplantation of organs, while as yet not having attained this complete success, he has clearly demonstrated certain principles of great importance. Before he began work we did not know that the kidney of one animal would functionate perfectly for several weeks in the body of another; we know that now. It is clear that Dr. Carrel himself believes that the experiment in making parts of two dogs’ legs grow as one indicates that this operation could be successfully performed on human beings. In an address delivered before Johns Hopkins University he declared a year ago that “ it is not unreasonable to believe that some transplantations, as, for instance, the transplantation of the arm a little above the elbow, may be successfully performed if an adequate technique is used.” The operation on a man would be easier than upon a dog simply because he is larger; the muscles, the bones, the arteries, and the veins could be more easily handled. Last summer in France Dr. Carrel experimented upon the leg of a human cadaver, and became familiar with the anatomic details involved in such an operation.

The fact that this new surgery may make wooden legs old-fashioned merely suggests its infinite possibilities. When science has demonstrated the practical uses of these operations, then the State will be confronted with the necessity of devising some means of obtaining the necessary material. The most obvious way—the use of organs of people recently dead, perhaps of executed criminals, or victims of sudden accidents—has already been suggested. In this problem, of course, there are important social and psychological considerations. What, for example, would be the mental effect upon a man of the constant realization of the fact that his body contained the organs of other people? There are other solutions of this problem with which science, should it ever become a practical question, will have to deal. It may be that a man could use in safety the kidneys of an anthropoid ape : these animals, however, are expensive and difficult to find. It is possible that some way might be devised of using the organs of an animal easier to obtain. At present this could not be done, for the reason already explained—that the blood serum of man would act as a poison upon its tissues: an animal, however, might be gradually and artificially accustomed to human blood. Perhaps the most available way out of this difficulty is found in the fact that the average human being can get along very well with one kidney. The operation known as nephrectomy—the removal of a kidney—is not uncommon. A man with two healthy organs might therefore sacrifice one to a sufferer closely allied in affection—his brother or his wife.