Great men have so many sides to their nature that in attempting to review their lives, too much emphasis on one side or another leads to distortion and gives either an exaggerated or a false idea of the kind of men they really were. Especially is this true of a man like Pasteur, whose many-sided personality presented so many aspects, each as delightful and as interesting as the other that in a paper as brief as this one must necessarily be, one cannot do justice to all of them and therefore must run the grave risk of overemphasizing one or more to the detriment of others equally interesting and equally important. However, although attempting to give at least an idea and suggestion of his many-sidedness, I propose, in view of the fact that this society is made up exclusively of scientifically minded men, to deal more especially with one phase of his personality, --- namely, the methods of approach he used in attempting to solve the many problems that confronted him during his long and fruitful life. To me, among many and varied emotion I have felt in reading about his life, the clear-cut logical mind he possessed and the way he used it have stood out among a myriad other equally impressive attributes of his personality; and this is the justification I claim in thus putting this side of his nature to the fore.
In the archives of France, the name of Pasteur is mentioned in the early part of the 17th century. His immediate lineage dates back to 1682. His three immediate predecessors were all tanners, his father being the last of his name to ply that trade. He, Jean Joseph Pasteur, had had a good and strict education; had fought with Napoleon and when the latter was exiled, was discharged from the Army, returning home to Dole, in the Eastern part of France, to follow his trade. On December 27, 1822, Louis Pasteur was born, the third child in a family of five, the first of whom died in infancy.
Soon after the children were born, the family moved to Arbois, a few miles away, where Louis spent his youth. He received his early training at the Ecole Primaire, where he was rated as only an average pupil. At that time he showed promise of becoming an artist, for he possessed no mean ability at portrait painting. Even at that time he had a good many friends of a literary nature who apparently saw signs of great promise in him. At the age of 15, he went to Paris to prepare for Ecole Normale, but returned home within the month because the homesickness was more than he could bear. He went then to college at Besaneon, a city not far away, where he stood second in his class. He was known there as being a very serious-minded and sober boy, absolutely sincere and possessed of very high ideals. He made many life-long friends. At the age of 20, he went up for the entrance examinations to the Ecole Normale, but made only fair grades. He entered instead the Barbet Boarding School in Paris, where, apart from his work he took in many lectures especially in Science and Philosophy, among them those by M.J. B. Dumas, who was destined later to become one of his firmest friends and supporters. One year later, he entered the Ecole Normale, 4th on the list.
At this time began the Scientific life which ensured him a place in the Hall of Fame. He had had courses in mineralogy in which he had been especially interested in crystallography. In 1846, two years later, he entered the laboratory of Balard, the famous physicist, where he became Laurent’s assistant. Laurent was partly instrumental in encouraging him to continue the study of crystallography. It was at this time that he made his startling discoveries on the nature of Tartaric Acid which was the forerunner of all the marvelous discoveries that were to follow.
Briefly, these experiments were as follows: It was known that the tartrates rotated polarized light to the right, while the paratartrates produced no rotation. Pasteur noticed that the tartrates had little faces on their angles, which had been previously overlooked. Thinking that the presence of these faces on certain angels probably explained their deviation of polarized light, he eagerly began to examine the crystals of paratartrate, expecting, since they did not rotate polarized light, to find them without faces. ;; but he remarked that some of them had faces on certain angles, while others had faces of the mirror image angels – just as the two ands are mirror images of each other. Theorizing then, he thought that if the two kinds of crystals were then put into solution and then examined as to their ability to rotate polarized light, the two contrary forms would give contrary deviations. With great excitement he tried the experiment and found out that not only was that theory true, but that as he has also surmised, the combination of the two kinds of crystals in equal parts in solution gave no deviation.
Characteristically, he became so excited that he rushed out of the building, grabbed the first man he could find, a curator, bore him to the garden, and in high glee proceeded to explain to him the experiment he had just made. Thus was solved the mystery of the competition of paratartaric or racemic acid, which had been puzzling chemists for a long time.
When Biot, one of the foremost chemists of his day, heard about these experiments by a man so young as Pasteur then was, he was inclined to become sarcastic, but keeping an open mind invited him to demonstrate to him his experiment, which Pasteur did to Biot’s satisfaction. Thus was formed a friendship between two men, with a difference in age of about 50 years – a friendship that was destined to be lasting and profound. That fact emphasizes all the more the difficulties that Pasteur had to overcome not only then, but all through his life, when one appreciates that notwithstanding the acceptance of his results by such an authority as Biot, many lesser men took exception to Pasteur’s results and invented excuses, many of them puerile, to attempt to prove that Pasteur could not be right. All his life, he had to fight men of that stamp in order, as he said, “that truth may prevail.” Many of his friends thought that Pasteur went out of his way to try to convince en who never would be convinced with absolute proof in their hands. His passion for justice and truth were such that he would go out of his way to try to convince the most bigoted and unworthy of men.
At 24, Pasteur was made professor of Physics at the Dijon Lycee, where he fulfilled is teaching duties assiduously. At 27, he went to Strasburg as Professor of Chemistry; while there he married the daughter of the Rector of the Academy. He made a fortunate choice in his wife, for she was extremely sympathetic with his ideas and even insisted that the laboratory should come first.
In the meantime, he had not lost interest in his crystals, and hearing that a certain manufacturer in Saxony had succeeded in manufacturing racemic acid, undertook a long and fruitful trip to Leipsig, Vienna, Prague and other places. HE exclaimed, when he heard about racemic acid, “ I will go to the ends of the world, if necessary, to obtain racemic acid.” The result of these travels was that he was able to obtain racemic acid from tartartic acid, an event of the first importance, and one that he had previously though to be impossible of accomplishment. Shortly thereafter, one whole sitting of the Academie was given up to Pasteur and his researches, of such paramount importance were these discoveries considered. He was also awarded the red ribbon of the Legion of Honour.
At 32, he was made Professor and Dean of the Faculty of Science at Lille, then only a struggling school. As a result of his efforts he transformed the school into a flourishing University. He own work, no matter how important, was always made subservient to the good of the school and students. His lectures required hours of preparation and as a result were so brilliant that they soon attracted huge classes. While there, he began scattering those gems of wisdom that fell from his lips so often in later life. One of his most pregnant utterances, and one that ruled his own life always, was that “Without Theory, practice is but routine hours born of habit. Theory alone can bring forth and develop the spirit of invention.”
It was while at Lille that he began those researches that led to Pasteur’s later title of “The Father of Bacteriology.” A Lille manufacturer came to him to ask him to solve some of the difficulties he had had in the manufacture of beet-root alcohol. Using the microscope, which was his constant companion and truest friend throughout his long career, he found upon examination of the sediment produced during the process of making the alcohol, that the glovules of yeast which were round when the alcohol was healthy became lengthened when alteration took place, and were oblong when fermentation became lactic. That simple observation put into practice insured the success of the process in the future. It was that, which upon long pondering, gave him the idea that there might be a common cause of fermentation in the form of microscopic beings. At that time the idea of “spontaneous generation” held full sway over scientific as well as popular minds; hence it was no small thing to dare to think so radically different, and more, later to maintain as he did that he knew there was a microbic cause of all fermentation.
He continued to pursue his studies on fermentation, studying the lactic acid fermentation of milk, in which he found tiny globules, similar to those of yeast. These studies were interrupted temporarily by an invitation to return to the Ecole Normale, as director of the Science department. Feeling that the school at Lille had been put upon its own feet, he accepted. In the meantime, he had been invited to canvas for a vacancy in the Academy of Sciences, which he did, although unsuccessfully. However, he did not regret the experience. He had also had the misfortune of losing his oldest daughter, who died of typhoid at Baroise, during his stay at Lille. Broken up considerably by this experience, he was inactive temporarily, but later returned to his labors.
He now began that famous series of experiments, on the cause of fermentation, for which he is most noted. These experiments occupied a period of years, and were interrupted by temporary excursions into the field of diseases of wines and other alcoholic beverages, and by researches on the diseases of silkworms. But these phenomena of fermentation always occupied a primary place in his attention and mind, and he invariably returned to their investigation when nothing of more pressing importance impended. Upon this question too