THE GROWTH OF A SCIENCE.*
SIR MICHAEL FOSTER, whose great treatise on physiology has long been the standard authority on that important subject in our schools of medicine, here reprints, with some additions, the admirable and pleasantly discursive lectures which be was invited to deliver at the Cooper Medical College in San Francisco last autumn. It may seem to many readers that medicine is par excellence a science in which the history of. the past can be little more than a record of failures and follies. What are we to learn, it will be asked, from the vagaries of a Sangrado, the rhodomontades of a Paracelsus,
or the solemn mumming of a Thomas Diafoirus ? We should be content with the amusement that a Moliere or a Le Sage has contrived to extract from these types, and let their science "go across the night" with the same reflection that Dogberry advised his watchmen to form on the passing of a knave. Yet even the warmest advocate of novelty may be convinced by the plea which Sir Michael Foster has put forward in his opening lecture. It is the more interesting because it was delivered on the very outposts of Western civilisation, in the city where—as Stevenson has said—the European of to-day may well feel like the Roman legionary who gazed out, twenty centuries ago, across the mysterious Channel to the silvet cliffs and happy islands with which fancy could deal as it listed. Sir Michael Foster thus defends his preoccupation with the past :—
" We are, all of us, even in this farthest West, even in this closing year of the nineteenth century, children of our fathers. What we are is in part only of our own making, the greater part of ourselves has come down to us from the past. What we know and what we' think is not a . new fountain gushing fresh from the barren rock of the unknown at the stroke of the rod of " Lectures ea the Hiltory of Physiology during the Sixteenth, Seventeenth, and Eighteenth Centuries, By kV AL.Poster. Cambridge: University Press. [9s.3 our own intellect, it is a stream which flows by us and through. us, fed by the far-off rivulets of long ago. As what we think and say to-day will mingle with and shape the thoughts of men in the years to come, so in the opinions and views which ire are proud to hold to-day, we may, by looking back, trace the into ence of the thoughts of those who have gone before. Tracking out how new thoughts are linked to old ones, seeing how an erroi cast into the stream of knowledge leaves a streak lasting _through many changes of the ways of man, noting the struggles thgh which a truth now rising to the surface, now seemingly lost in the depths, eventually swims triumphant on the flood, we may perhaps the better learn to appraise our present knowledge, and the more rightly judge which of the thoughts of to-day is on the direct line of progress, carrying the truth of yesterdayon to that of to-morrow, and which is a mere fragment of the hour, floating conspicuous on the surface now, but destined soon to sink, and later to be wholly forgot."
A remarkable illustration of the truth of this fine passage is to be found in the seventh of these lectures, which deals with the English school of physiology in the seventeenth century, and especially with their views on the process of respiration. It is familiar to every schoolboy who has gone in chemist as far as what Mr. Wells wittily calls "the Three Gases" that the true meaning of respiration and combustion--the union of the oxygen of the air with carbon in the tissues of the body or in a burning object—was first made clear to the world by Lavoisier in the troublous times of the French Revolution. But Sir Michael Foster reminds us that the true explanation had been perceived, more than a century before Lavoisier, by John Mayow, a Cornish Fellow of All Souls, who was snatched away from science at the early age of thirty-five, and so had no chance of urging his theory on the acceptance of the busy world. In a little tract published in 1668 Mayow showed quite cogently that it was not the whole air, which was absorbed in breathing, but only a particular part of the air,—the part, in fact, that we now call oxygen. He under- took to show "that this air which surrounds us, and which, since by. its tenuity it escapes the sharpness of our eyes, seems to those who think about it to be an empty space, is impreg- nated with a certain universal salt of a nitro-saline nature, that is to say, with a vital, fiery, and in the highest degree fermentative spirit." He further recognised—what was the essence of Lavoisier's great discovery, and so the foundation of all modern chemistry—that in the process of combustion the " igneo-aerial particles" of this "universal salt" or "fiery spirit" entered into combination with the substance burnt. Then came Stahl, with his ingenious but inaccurate theory of "phlogiston," which was supposed to pervade all bodies, and to be expelled from them when they were burnt. For a century this theory held the field, and obstructed chemical advance. It never occurred to any one to test Stahl's theory by the simplest of all possible experiments,—that of weigh- ing the product of every kind of combustion to see if it were really lighter by the loss of "phlogiston." People contented themselves with their common knowledge that the residue in some cases, like the ashes of wood or tobacco, was obviously far lighter than the original substance, while a candle wholly disappeared. Yet in the book aforesaid Mayow had described the very experiment that convinced Lavoisier :—" Nor must the following point be passed over, that antimonium burned by the sun's rays (collected by a burning-glass) increases considerably in weight; as may be proved by experiment (ie., by actual weighing). Now we can hardly conceive that the increase of weight of the antimoniem arises from anything else than from the igneo-aerial particles inserted into it during the calcination." In other words, a metal which undergoes oxidation increases in weight by the amount of oxygen that combines with it. There is no more curious instance of the useless appearance of a great dis- covery before the world was ripe for it. "What a zigzag path, how unlike a straight line, is man's progress in search of truth. Here is Mayow reaching a point far ahead, and Boyle a little later had grasped the same fact; Stahl drags, or seems to drag, the whole world of thought back; and more than a hundred years afterwards, Lavoisier reaches the same point as Mayow. How true it is " (adds Sir Michael Foster) "that the value of a truth is not absolute; there is a time and a place for everything, including a new truth. If a discovery is made before its time, it withers V barren, without progeny, AS did Mayow's." This is a very suggestive remark. One cannot but wonder whether in the twenty-fifth century writers on the nineteenth will reallY speak of us in the terms that we are only too ready- to apply to ourselves, as bold and honest seekers for all truth, or whether we shall be set down as careless rejectors of the germs of greater truths than we yet possess, or even as deliberate obscurantists. Those who believe in the occult forms of " science " that the psychical researchers and the faith-healers and the theosophists profess to study will, of course, have no doubts on that head. Certainly such a survey of the past as Sir Michael Foster has here taken is eminently adapted to inculcate modesty.
We have left ourselves little space for dealing with the details of his work, which are, indeed, mostly too technical for discussion here, although the book is written with a general simplicity of phrase and lucidity of exposition that should make it easy and instructive reading to the intelligent layman. The history of physiology is anything but a dry subject, even to those who never handled a scalpel or heard of the plethys- mograph. "A knowledge of the laws which govern the phenomena of all living things is so essentially the basis of all attempts to succour, or to watch over the welfare of one set of beings, that the history of physiology cannot be regarded in any other light than as the heart or kernel of the history of medicine." We may add that it should be very interesting even to non-medical readers to trace the steps by which during three centuries man slowly pressed on to a fairly complete knowledge of the secrets and mechanism of his own body. Sir Michael Foster begins with Vesalius, who put anatomy on the basis of first-hand investigation rather than of the interpretation of Galen, and so replaced the rule of authority in medicine by that of science. The second lecture deals with Harvey and the circulation of the blood, and shows the origin and rise of the experimental method in physiology. The remaining lectures, whose arrangement is partly by date and partly by subject, deal respectively with the introduction of the new physical methods into the study of the human frame—the first attempt to make physiology, as Huxley said, a branch of engineering—with Malpighi and the study of gland and tissue, with Paracelsus and Van Helmont and the rise of physiological chemistry, with the study of the two great problems of respiration and digestion—these occupy four lectures—and with the older doctrines of the nervous system. The last lecture is par- ticularly interesting; but, indeed, we can recommend this admirable and suggestive book with confidence to all, laymen or doctors, who wish to trace the gradual growth of man's knowledge of the physical basis of his life.
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