These two discoveries by Bernard--the formation of sugar by the liver and the nervous vasomotor mechanism--are, in their far-reaching application and their precious suggestiveness for other investigators, the most significant advances in physiology of the nineteenth century. They are directly due to a great imaginative faculty informing a most fertile inquiring spirit. Bernard was very different from his master, Magendie, in his applications of the experimental method. Magendie's researches were made more or less at random in the great undiscovered regions of physiology. He made his experiments as so many questions of nature. He cared not what the answer might be. He seldom had an inkling beforehand where his experiments might carry him. As he said himself, he was a rag-picker by the dust-heap of science, hoping to glean where others had missed treasures, and not knowing what his stick might turn up next. Bernard's experiments were always made with a definite idea as to what he sought. Not infrequently his pre-conceived theory proved to be a mistake. It is of the very [{284}] genius of the man that he was able to recognize such errors, and that he did not attempt to divert the results of experiments so as to bolster up what looked like eminently rational theories. The imaginative faculty that had come so near perverting him to literature was a precious source of inspiration and initiative in his scientific work. It was not followed as an infallible guide, however, but only as a suggestive director of the course investigation should take.
Besides the important discoveries made by Bernard there are two minor investigations, successfully accomplished, that deserve a passing word. To Claude Bernard we owe the use of curare in physiological experimentation. Curare is an Indian arrow poison which absolutely prevents all muscular movement. If artificial respiration is kept up, however, the animal lives on indefinitely, and no motion will disturb the progress of the most delicate experiment. In Bernard's time it was thought that the drug did not affect the sensory nervous system at all, and that as a consequence, though absolutely immobile, the animal might be suffering the most excruciating pain. We now know that the sensory system is also affected, and that the animal in these experiments suffers little if at all.
Bernard's investigation of the effect of carbonic oxide gas will probably be of more practical benefit to this generation and the next than it was to his. Like most of Bernard's discoveries, this one threw great light on important questions in physiology quite apart from the subject under investigation. Carbonic oxide is the gas produced by incomplete combustion of coal. The blue flames on the surface of a coal fire when coal is freshly added are mainly composed of this gas in combustion. From burning charcoal it is given off in considerable quantities. The gas is extremely poisonous. Unlike carbon dioxide, which does harm by shutting off the supply [{285}] of oxygen, carbonic oxide is actively poisonous. After death the blood of its victims, instead of being of a dark reddish-blue, is of a bright pinkish-red. Bernard's study of the change that had taken place in the blood showed that the hemoglobin of the red blood-cells had united with the carbonic oxide present in the lungs to form a stable compound. The usual interchange of oxygen and carbon dioxide in the tissues could not take place. The combinations formed between oxygen and carbon dioxide and the hemoglobin of the blood readily submit to exchanges of their gaseous elements, and so respiratory processes are kept up.
Before Bernard's discovery it was thought that the respiratory oxygen was mostly carried dissolved in the blood-plasma--that is, in the watery part of the blood--or at least that its combination was a physical rather than a chemical process. This idea was overthrown by the discovery that the carbonic oxide combination with hemoglobin was very permanent. The rôle of the red blood-cell in internal respiration took on a new importance because of the discovery, and the comprehension of anaemic states of the system became much easier.
About the middle of his career Bernard suffered from a succession of attacks of a mysterious malady that we now recognize to have been appendicitis. Once at least his life was despaired of, and recurring attacks made life miserable. After a year of enforced rest on the old farm of his boyhood, now become his own, he seems to have recovered more or less completely. His health, however, was never so robust as before. Toward the end of his life he lived alone. His wife and daughters were separated from him, and one of the daughters devoted her time and means to suffering animals in order to make up, as she proclaimed, for all her father's cruelty.
Bernard lived almost directly opposite to the Collège de France, in a small apartment in the rue des Ecoles. An old family servant took care of him, and his life was one of uttermost simplicity, devoted only to science. Once at court, in 1869, Napoleon III insisted on knowing, after an hour's conversation with him, what he could do for him. Bernard asked only for new facilities for his experimental work, and new apparatus and space for his laboratory.
Honors came to him, but left him modest as before. He was elected a member of the French Academy--one of the forty immortals. Only five times in the history of the Academy has the honor of membership been conferred upon a medical man. Before Bernard, Flourens, the father of brain physiology, had occupied a fauteuil, while Cabanis and Vicq d'Azyr are two other names of medical immortals.
Bernard was elected to the 24th fauteuil, which had been occupied by Flourens, and according to custom had to pronounce his predecessor's panegyric. The conclusion of his address was the expression: "There is no longer a line of demarcation between physiology and psychology." Physiology had become the all-ruler for Bernard in human function, and he drifted into what would have been simple materialism only for the saving grace of his own utter sanity, his active imagination, and the unconscious influence of early training. During his most successful years of scientific investigation, wrapped up in his experiments and their suggestions, Bernard was drawn far away from the spiritual side of things. This partial view of man and nature could not endure, however. In an article on Bernard in the Revue des Questions scientifiques for April, 1880, Father G. Hahn, S. J., says of him: "A man of such uprightness of character could not be allowed to persist to the end in this restless skepticism. His mental condition was really a kind of vertigo caused by the [{287}] depths of nature that he saw all around him. At the threshold of eternity he came back to his true self and his good sense triumphed. The great physiologist died a true Christian."
Bernard was one of the great thinkers of an age whose progress in science will stamp it as one of the most successful periods of advance in human thought. He accomplished much, but much more he seemed to have divined. He seldom gave out the slightest hint of the tendencies of his mind, or of his expectations of discovery in matters of science, until fully satisfied that his theoretic considerations were justified and confirmed by observation and experiment. In one thing, however, he allowed favored friends to share some of his anticipations, and the notes published after his death show that he was on the very point of another great discovery in biology which has since been made. He was a firm friend of Pasteur's, and had ably seconded the great chemist-biologist's efforts to disprove spontaneous generation. Bernard's demonstration that air passed through a tube heated red hot might be suffered with impunity to come in contact with any sort of organic material, yet would never cause the development of germ life, was an important link in the proof that if life were carefully destroyed, no life, however microscopic in character, would develop unless the seeds of previously existent life were somehow brought in contact with the organic matter.