Eve suppers described in Europe as if they were the orgies of Heliogabalus? This may all be explained exactly as was the evil reputation of the last century of the Republic and the first century of the Empire, as compared with the second century: because in America the Puritan origin of the state is still not far behind us, and the reaction of the moral consciousness is greater than it is in Europe against the progress of that extravagance, corruption, and vice which accompany a rich, urban, mercantile civilization. In Europe, on the other hand, the moral consciousness has for a long time been accustomed to consider all this as inevitable and, for the present at least, impossible to reform, and therefore makes no protest; exactly as the men of the second century no longer cried out against those many evils which were intolerable to the men of the first century. In America, there is still protest; in Europe, there is silence; therefore superficial observers conclude that in the one place there is vice, in the other none, while in reality evil exists on both sides of the ocean, but on the American side there is still faith that it may be extirpated, and there is a will to attempt the work of purification. On our side the present conditions are accepted without a word, just as they are, the good with the bad. Who is right? Who is wrong? I may only say such is the present situation.

Under this very important aspect, the condition of the United States is much nearer to that of ancient Rome than is the condition of the present-day Europe. And this explains to me why this side of my history has been more quickly and profoundly understood in America than it has in Europe. The chief reason which attracted Theodore Roosevelt to my book he told me this more than once in Washington --was the struggle between two principles

which I had described, and which had seemed to him to shed so much light on the confusion and excitement of men and things which stir the United States at the present day. How often have I heard this same observation made in private conversation and public speech, in New York as well as in Boston, in Philadelphia as well as in Chicago! Indeed in Chicago the similarity between American and Roman puritanism was the subject of an interesting after-dinner speech delivered by my host, a banker, a young and brilliant man, in the presence of leading business men at a dinner given in my honor at the Chicago Club. I shall never forget that speech, so enthusiastic was the speaker, and so delighted at having been shown his America in the long-ago life of Rome. In answering him I had to say that, as everything in Chicago is the greatest in the world, it was in Chicago that I had found my greatest admirer in the world!

However, it is North America alone that resembles ancient Rome. South America, or at least the South America which I know, -Brazil and the Argentine Republic,- does not. Those states represent, rather, the continuation and the development of the old European civilization, which is something quite different and opposed to it. In those states, extravagance occupies the high social rank that it does in Europe. The rich make a show of it, the people admire it, religion does not seek to restrain it, art and manufactures thrive upon it, the traditions of the past, as well as the tendencies of the present, favor it in every way according to the means that each has at its disposal. This difference of origin and development between the two Americas is more important than is generally supposed, and an understanding of its importance may be greatly helped forward by a study of Roman history.

I

MODERN medicine depends so largely upon animal experimentation, that, without it, the healing art would still remain a mere mixture of empiricism and superstition, as is the case in China to-day. Both the moral and legal codes forbid experimentation on human beings without their own consent; and as the results obtained from cold-blooded animals are commonly inapplicable to ourselves we are obliged to conduct our researches on the bodies of our nearest relatives, the warm-blooded lower animals. The ancients derived much of their medical knowledge from this source: we find the great Galen conducting extensive and profitable researches on apes and dogs. In the Middle Ages, however, the deadening influence of scholasticism discouraged animal experimentation; we are therefore not surprised to learn that for over a thousand years medicine stood still.

With the great intellectual awakening that characterized the so-called Renaissance, the teachings of the ancients were felt to be insufficient. Vesalius and others studied the structure of the human body as thoroughly as the prejudices of the time permitted; progress in the science of physiology began; surgery threw off its old association with the barber's trade. In the seventeenth century, the invention of the microscope led to the assiduous study of our more minute structure. Nevertheless, if investigators had limited themselves exclusively to the con

sideration of the human body, alive and dead, healthy and diseased, the science and practice of medicine could not have continued to advance. This limitation restricts us too closely to actual conditions; it excludes all such as are hypothetical or artificial. The voluntary submission of a human subject for medical experimentation is rarely obtainable, though a number of physicians, from grand old John Hunter to our own brave Lazear, have offered their persons and risked their lives in the interests of medical science. Such instances of noble self-devotion are infrequent, and should remain so; they are justified only by the direst necessity. It is indefensible to experiment upon men, when information equally, or almost equally, worthy of confidence can be derived from the lower animals.

The appreciation of this rather elementary moral principle has led to the marvelous progress in medicine that is one of the triumphs of our age. I would not pretend that the science and practice of medicine - two very different things, by the way - are anywhere near perfection; but it is true that the greater part of the physical ills of humanity are to-day under the physician's control, while only a very few remain altogether beyond our reach. Indeed, Metchnikoff, one of the ablest investigators on animals, thinks that there is a prospect of a fairly successful fight to defer the approach of man's greatest enemy, old age.

Cruelty to animals is abhorrent to modern civilization; it lowers man to 7

the level of the brute, and, in the case of warm-blooded animals, it is punishable at law. This characterization applies, however, solely to wanton cruelty, for even an act of true kindness may involve cruelty. In this connection it is my duty to do what should be unnecessary, and is certainly highly distasteful to me as a physician, but which seems to be demanded by some of our critics, namely, to remove the widely prevalent impression that familiarity with suffering breeds callousness. The best evidence against this impression is the conduct of the medical profession itself.

Our critics must remember that the only notice we take of suffering is to try to assuage it, that our most distressing experience is to witness suffering which cannot be relieved, and that we take as much satisfaction in banishing pain as in saving life. As for our supposed indifference to animal suffering, merely to state that the infliction of pain actually interferes with the usefulness of most animal experiments, will convince well-meaning but uninformed persons that, whenever possible, operations on animals are conducted under the same methods of anæsthesia that are applied to human beings.

We destroy lions and wolves, not to speak of mice and rats, merely because they attack our lives or property whenever they can. Their interests are opposed to ours, and that seals their fate. The investigations upon animals which tend to subserve our interests, at the expense of theirs, should be considered from the same point of view. It may seem harsh, but it is only logical to characterize the man who subordinates the health and happiness of his fellow men to the comfort of some rabbits and dogs, as an enemy to mankind. The old Roman law justly regarded this as the basest of all crimes.

II

Many well-intentioned persons, who earnestly desire the limitation of vivisection to what is actually necessary, believe that a restriction to practical ends would fulfill the ideal of both minimizing cruelty and fostering medical progress. These people are unaware of the fact that there are two sides to medicine, namely, medical science, or rather the medical sciences, and the medical art, commonly called the practice of medicine and surgery.

It is a philosophic principle that a pure science cannot be practical, but deals solely with observed facts, theories, and hypotheses. The application of a science to practical ends is more properly called a useful art. In the medical sciences we study the structure of the human body, its composition, its functions in health, the impairment it suffers from disease, and the remedies for disease. In the practice of medicine we do not treat diseases but patients. The practicing physician is confronted with a sick man, not with an abstract question. He endeavors to apply his scientific knowledge to the aid of his patient, but he does not regard him as a scientific problem. This point is misunderstood by many people, and has led to the unwarranted and scandalous assertion that hospital patients are frequently the objects of experiments. The exact contrary is true: with a few unavoidable exceptions, no procedure is tried upon a human being that has not been proved harmless to the lower animals. The misdirected energies of the anti-vivisectionists' merely tend to increase the number of exceptions to this rule.

Physiology, which deals with the functions of the healthy body, is, like anatomy, fundamental to the medical sciences. Many of the deficiencies of modern medicine are due to gaps in our

physiological knowledge, while much of our progress in treatment is the result of recent advance in this science. As examples, I may mention the modern methods of dieting, exercise, change of climate, and regulation of regimen in its broadest sense. I must not, however, ignore the vast improvement in medication with drugs, which is a consequence of our advance in what physicians call pathological physiology, meaning thereby the perverted physiology of the diseased body. We are learning to appreciate the various compensations, whereby a diseased organ is more or less replaced by one that is still sound; and also that great compensatory scheme, which enables a generally diseased body to remain not only alive, but even fairly efficient. One can see how this knowledge may be utilized to the advantage of what the insurance companies call impaired risks; it is safe to say that the lease of life of sufferers from diabetes, heart disease, and Bright's disease, has been doubled within recent years.

The ancient physicians believed that the arteries contained air; that, indeed, is the meaning of the word artery. Galen proved that they contained blood, by cutting them in living animals; there was no other way of settling this fundamental fact, for, in the dead body, the arteries are quite empty. The circulation of the blood was demonstrated by Harvey through experiments on dogs. The capillaries, connecting the arteries and veins, were first seen by Malpighi in the lung of a living frog. It is evident that these observations could not have been made in any other way. The nineteenth century has greatly advanced our knowledge of the wonderful pumping and pipe-line system within our bodies. We now know the speed of the blood-current, its volume and its force, and have a fair idea of the nervous mechanism which controls it. To study

these problems, it has been necessary to attach the most varied physical apparatus to the heart and blood-vessels of living animals; it will, however, reassure the reader to learn that to be of real value these experiments must be conducted under anæsthesia. Without them, we should not have the faintest clue to the successful treatment of patients suffering from heart disease.

In the study of the physiology of respiration, little can be learned from the observation of living and healthy men, that does not need corroboration through experiments on animals. As instances, I may mention the demonstration that the aeration of the blood takes place in the capillaries of the lungs; the apparently simple facts that we cannot live without oxygen, and that air which has been once breathed is poisonous; the action of the muscles of respiration, and the nerve-supply which directs them. Not one of these points could have been investigated save by the sacrifice of a number of animals. The whole subject of artificial respiration, so important in the resuscitation of asphyxiated human beings, has been and still is in process of discovery from experimentation on the lower animals. I need only call attention to the newly proposed methods of resuscitation from electric shocks, which would deserve no attention whatever if they did not appear successful when applied to animals.

Proceeding to the study of digestion, let us begin by noting that only its earlier and less important stages are accessible in the intact bodies of men or animals; even so we must employ the extremely uncomfortable stomach-tube, which cannot be used very frequently without starving the subject under investigation, and yields at best but very fragmentary scientific results. The first really valuable investigations were made by Beaumont, about 1830, on a

Canadian, one Alexis Saint-Martin, who suffered from a gunshot wound of the stomach, which had failed to close. Since then one or two other victims of this so-called gastric fistula have been studied, but such cases as these are far too rare to suffice for rapid scientific progress. It has therefore become necessary to perform similar experiments and investigations on dogs, whose stomach-digestion is very much like ours. These dogs, fitted with an artificial external opening in the stomach, through which food may be poured in and withdrawn, feel no more pain than did Beaumont's Canadian, who enjoyed excellent health through years of observation.

These experiments have shown how the gastric juice begins to flow at the very sight of food; how the food is changed in the course of its sojourn in the stomach; how some substances favor digestion, and others interfere with it; how the stomach moves, and how it is finally emptied. Without actual observation we should have to guess at these and nearly all the other phenomena of stomach-digestion.

The digestion which goes on in the intestine is far more important than that in the stomach itself, and it is hardly necessary to inform the reader that we should know absolutely nothing about it unless we had studied it in animals. The same is true of the functions of the great digestive glands, the liver and the pancreas; likewise of the great solar plexus of nerves which controls the whole apparatus. In this vast department of physiology new facts are continually coming to light, as operations on animals become more and more specialized.

In passing, I should refer again to one fact which is often disregarded. Digestive experiments on animals which are suffering pain are quite unsatisfactory; it is needless to add that pain had to

be inflicted to prove this point, which otherwise would merely be suspected.

Closely connected with the above experiments are those which instruct us in the subjects of nutrition and of tissue-change. We have learned how to grow fat and how to reduce weight, what it means to be hungry or to be satiated. Some of these studies can be carried out on the human subject, but those suspected of being dangerous to health must be made on the lower animals. It is natural, therefore, that some of the dogs in the laboratories will be overfed and others half-starved; this is inevitable.

It is highly significant of the dense ignorance of our grandfathers, that so fantastic and absurd a system as Gall's phrenology was accepted even by some physicians as a likely explanation of brain physiology; I am afraid that many intelligent persons still believe in phrenology. Through experiments on the brains of living animals we have learned which portions of the brain control the muscles, which experience the sensation of pain, which regulate the body's temperature, the act of breathing, the senses of sight and hearing, and which govern the other bodily functions. Most of these investigations necessarily consisted in irritating or removing portions of the brain, and some very few forms of research had inevitably to be conducted without anæsthesia. To understand what pain is, we unfortunately must cause it. It is a most instructive fact, that those portions of the brain about which we know least are the very ones that are poorly developed in the lower animals; progress has been arrested chiefly because animal investigation is no longer available. We must recall, too, that the previous experiments on cold-blooded animals, whose brain-functions are of an altogether lower type than ours, had yielded little that could be applied