Lavoisier’s mind seemed always preoccupied with questions relating to the grandeur and progress of humanity in its entirety. Here is a single example of the truth of this statement:—
When he learned from his own observations that the exhalation of carbonic acid increased during physical work, he drew the conclusion that men who are obliged to perform severe labor stand in need of a more abundant nourishment than is required by ordinary workmen in order to recover the carbon which had been expended in their severe labors; and he immediately urged that an effort be made to furnish the working class with better nourishment. The public functionary—he wrote at the end of his treatise on respiration (published in 1789)—is not the only individual who works for his country. The man of science, he added, is also fulfilling his patriotic duty when he teaches, by his investigations, how the misery which exists in the world may be alleviated. And if he accomplishes nothing more than to add a few years, or even only a few days, to the average duration of the life of man, he still may with justice claim the right to be given the glorious title of “benefactor of humanity.” (J. Rosenthal.)
France, at the time when Lavoisier wrote his treatise on respiration, was in the throes of a great revolution, out of which came the Republic. But this republic showed no gratitude to Lavoisier for the services which he had rendered to his country; for, on the 8th of May, 1794, it executed him without any specific charge having been brought against him, simply because he had held the hated office of Government Collector of Taxes. When one of Lavoisier’s personal friends, just before the prisoner was removed to the guillotine, called the judge’s attention to his scientific merits, this functionary replied: “We no longer have any use for men of science.”
Before closing this necessarily brief and somewhat superficial account of the work accomplished by the great French chemist, Lavoisier, I must beg permission to refer very briefly to the views which he entertained on the subject of heat-production. The chief significance of these studies of the fundamental phenomena of animal life is this: they afforded for the first time a solid basis for the theory of heat-production in living animals. This theory, formulated in greater detail, may be stated in the following terms, which I copy in all important respects from the memoir published by Rosenthal:—The tissues which compose the body of the animal, and which are themselves composed of carbon, hydrogen, oxygen and azote, possess the power of assimilating a further quantity of oxygen, a quantity somewhat greater than that which they already contain; and, by reason of this fact, they are able, as combustion advances, to accomplish two things—first, to combine with the surplus oxygen furnished by respiration; and, second, to form carbonic acid, water and certain azotic matters that are discharged from the body. It is this process of combustion which gives rise to heat in the animal’s body and in addition is associated with a certain loss in its weight. This loss, however, is limited, for the furnishing of new elements is going on simultaneously with the casting off of the old, thus restricting the loss of weight.
It is to Lavoisier that the imperishable honor belongs of formulating the chemical theory of respiration, and of thereby founding a new era in physiology—the modern era. (Claude Bernard.)
Too much stress cannot be laid upon the truth of this declaration made by Claude Bernard, the great modern authority in physiology, concerning this, the most important advance secured for the science of medicine during the eighteenth century. But alas! many years had to elapse before the physiologists of that period were able to appreciate the importance of Lavoisier’s discovery. Very soon after the announcement of this new theory the leading chemists of Europe returned almost as a single body to the old phlogiston doctrine.
Lavoisier’s portrait is shown in the frontispiece of the present volume.
BOOK VII
MEDICINE IN ENGLAND