Louis Pasteur

BY: H.L. Russell

Louis PasteurA FULL-BEARDED man, grisly gray both as to hair and beard, with a stiff leg that at once made you think of a soldier who carried still the scars of battle, stumped his way among the desks of the young doctors and students of the famous Institute Pasteur. This was my first, vision of the great French scientist, Louis Pasteur that I had, as a student in his laboratory in Paris, nearly forty years ago.

The world was then ringing with acclaim for the wonderful results that he had been securing in saving the hundreds of lives of terror-stricken people, from all parts of Europe from the dread scourge of hydrophobia. The great Institute had only been opened two or three years before by a grateful people in recognition of Pasteur's services for the benefit of mankind.

This scientist, whom Sir William Osier, the world-famous English physician, designated as "the most perfect man who has ever entered the kingdom of science," is known to the mass of mankind mainly for his discoveries as to the cause, of infectious disease. To the scientist, Pasteur's fame rests quite as much on his earlier brilliant discoveries in the field of fermentation and decomposition as in the realm of disease. Some of his most fundamental work was in chemical research, for he was a chemist before he was a biologist and a bacteriologist.
Louis Pasteur was born December 27, 1822. He" was the son of a tanner, in the town of Arbois, who had formerly been a soldier in Napoleons army. His ancestry can be traced back in a direct line another 1.50 years. His great-grandfather, Claude Etienne Pasteur, obtained freedom from serfdom in 1763.
Pasteur, early in his life, showed a keen desire for an education and demonstrated his scientific turn of mind. He also proved himself a capable portrait painter, winning many prizes for his accomplishments. His education was obtained "at several different schools in the vicinity of his home and in Paris. He was given the position of preparation master at the Royal College of Besancon before reaching his eighteenth birthday and from then on he was engaged in educational work almost constantly.

His first great interest was that of chemistry. The study of crystals occupied his attention and in this science of crvstalloraphv he made some original discoveries while yet a very young man. His rise in the scientific and educational world was rapid. In 1848, at the age of 25, he was appointed professor of physics at Dijon and the following year professor of chemistry at Strasburg. His scientific achievements won for him election to the Legion of Honor in 1853 and in the following year lie was made Professor and Dean of the new Lille Faculty of Science. It was here that, he introduced laboratory work into the instruction of students as a supplement, to the lecture method. His advance continued and in 1857 he was appointed administrator of Ecole Normale and in December, 1862, just. before his fortieth birthday he was elected to the Academic des Sciences.

The dairy interests of the world owe much to the inspiring studies of Pasteur. It was his foundation work in the realm of the "infinitely little" that laid the first course in the temple of fact on which the enduring success of modern dairying is built. Milk has been subject to spoilage on contact with the air since man first domesticated the cow and the goat. But why? This no one knew. So common a fact was this that, it needed no explanation. It, was so because it was so. But this explanation that, did not explain did not satisfy the young French chemist.

Organic liquids of all kinds inevitably and invariably soured, fermented, spoiled. The juice of fruits generally developed alcohol and carbonic acid gas. Milk, on the other hand, soured, turned rancid, and became unfit, for use. With the aid of the microscope, the laboratory worker had found in fermenting liquids of all kinds, microscopic cells (yeasts and bacteria) that, apparently were able to multiply and grow. Pasteur had been able to detect differences between yeasts and the smaller, more elongated bacteria. By means, of a series of brilliant, experiments, he proved that fermentation was connected with life; that there was no inherent, necessity of decay or fermentative change, unless contamination gained access from outside.

The great Liebig, whose renown as a leading chemist was acknowledged the world over, had rejected the idea that life had anything to do with the processes of fermentation. He believed that, ferment was readily alterable- organic substance which easily underwent decomposition, and thus set in motion additional molecules, of fermentative matter. The prestige of the older German scientist, who was then the leader of modern chemical thought, regarding the relation of plant growth to the soil, so dominated the situation that the views of the young Frenchman found few disciples who were willing to accept, them. Pasteur's contribution to the explanation of the souring of milk conclusively showed that the lactic acid fermentation was due to the acidity of certain specific bacteria. One of his early contributions was entitled, a "Treatise on the Fermentation Known as Lactic." From this discovery he was led to further study of milk in that often he found other types of fermentation than those connected with normal souring.

To show the keenness of his powers of observation, this interesting experience may be worth relating. Examining one day a sample of spoiled milk, lie noted that the minute organisms showed marked powers of motion when examined under the cover-glass of a. microscopy preparation. On the edge of this preparation where the opportunity for absorption of the oxygen of the air was greater, the ability of the living organisms to move seemed to be impaired. This certainly was a peculiar condition of affairs. All life demands oxygen for the continuance of its functional activity. Here, however, was a condition in which air seemed not, only unnecessary, but actually detrimental. 

Nobody but a person imbued with the keenest power of observation would have been able to recognize this peculiarity. Pasteur saw at once that- here was something different from normal experience. If the oxygen of the air had this disturbing- effect, he could prove this by introducing a current, of air into the liquid and see what happened. This he did, and to his keen satisfaction the organisms that had been actively in motion lost their power of movement, and the fermentative property ceased. Here was the discovery of an entirely new principle, the fact that some types of bacteria could perform their functions better in an atmosphere devoid of free oxygen than otherwise. To this class. Pasteur gave the new term, anaerobes, organisms that are able to live without air. This peculiar fermentation proved to be the butyric acid type of change that is the cause of the rancidity of butter, an abnormal fermentation that is of much import in the dairy business. 

Pasteur's studies later on the spontaneous generation of matter proved indisputably that life came from pre-existing life: that the processes of fermentation, putrefaction, and decay did not originate in and of themselves but invariably came from pre-existing microscopic forms of life. With our modern equipment and present-day notions, one wonders why such wild-eyed dreams gained credence, but it is much easier to look backward than forward; distance or difficulties do not seem half as hard as we look behind us compared with what they are when we attempt to penetrate the gloom ahead.

Pasteur was a natural born doubter and it was to this quality that lie owed much of his success as a discoverer of new ideas. Writing to Pouchet about the subject, of spontaneous generation, he said, "In experimental science it is always a mistake not to doubt when facts do not compel affirmation." This critical attitude enabled him to test and retest his results so his conclusions were bullet proof before they were given out. 

From this field of spontaneous generation he was led to study the so called disease of wine. The vineyard industries of southern France had been imperiled thru "sickness" of wines that destroyed their fine aroma and flavor. "Sick" wine became turbid', sour, off in flavor, ruined as a beverage. To his beloved France this was a grievous blight-like the plague of Egypt. 

It was easy to prevent, this trouble, by boiling the wine; but the high temperature used injured the flavor or bouquet, as it is called. Finally, in the fall of 1864, Pasteur found it, was sufficient, to heat the wine for a few minutes to a temperature of 122 degrees to 140 degrees Fahrenheit. This lower temperature fortunately did not destroy the fine aroma. But it was quite a while before this simple process was accepted by the French exporters; not until a cargo of wine had been shipped for a long journey thru the tropics did prejudice and jealousy yield to scientific progress. Some said this heating process would "mummify" the wine and so prevent its aging.

In Austria, where the method was also quickly adopted, the process was called Pasteurization, in honor of the French bacteriologist. It was this same principle that, was later applied to the treatment, of milk to increase its keeping quality. The secret of success in the pasteurization of milk lies in the fact that the major part of the inevitable changes that, accompany souring or other fermentative changes is due to the presence of bacteria that in the rapidly growing stage are readily killed by a scalding temperature. This point, known as the thermal death point of the growing organism, is fortunately just below the temperature at which the cream line in milk is affected. Even disease bacteria, such as tuberculosis, diphtheria, typhoid, and other organisms are not able to endure the temperature of pasteurization.

This method was first, applied to the treatment of milk in Europe but it was in America, that the process was commercialized and put on a practical basis. In the earlier days the process was applied primarily to the treatment of milk for infant, feeding and ailing children, but the success in this field soon led to its more general application in the treatment of city milk supplies. America has developed this. phase of the dairy business to an exceptionally high stage of perfection. Without doubt, the very wide use of fluid milk in the United States compared with other countries is due in no small measure to the feeling of security that the public have in the healthfulness of the product, both from the hygienic as well as the nutritive point, of view. 

Pasteur was, first of all, a humanitarian. He dearly loved his parents, his brothers and sisters, and his family and his love extended to all his fellow-men. It was this love that prompted him to undertake his researches to relieve their physical sufferings and the hardships caused by constant economic losses.
The silkworm disease was studied by him in 1865 which he later solved, and an epidemic of cholera demanded his attention the same year. His love for science was aptly illustrated when Emperor Napoleon III and Empress Eugenie, following a demonstration of his wine study, manifested surprise that" he did not turn his discovery to profit. He replied, "In France scientists would consider that they lowered themselves by doing so."

It was Pasteur's discoveries which led others to improve surgical methods with regard to sanitation. He discovered the cause of puerperal fever in 1878, of chicken cholera in 1880, and of hydrophobia in 1881, and made important studies on yellow fever the same year. His most, famous contribution, the treatment for hydrophobia, was first applied in 1885 and within a year great contributions were received for the establishment of the Institute Pasteur, which was completed late in 1888. More than two and a half million francs, were obtained. 

Another contribution which is of direct and inestimable value to the dairy industry was his discovery in 1877 of the cause of anthrax and his development four years later of the method of vaccinating for preventing this costly disease. Pasteur, unlike many early scientists, lived to see his findings accepted and to win the applause and approval of the entire civilized world. He and his work were acclaimed in every scientific group and in 1882 he was elected to the exclusive Academic Franeaise. Pasteur also experienced the pleasure, before his death on September 28, 1895, of seeing his former students and associates, building on his own work, make new discoveries for the benefit of human progress.

The dairy industry owes no inconsiderable debt to the fundamental work which the great, Pasteur did to put, scientific accuracy m place of hypothesis and surmise in the development of this important, branch of science.

H. L. Russell is dean of the Wisconsin College of Agriculture. He is a native of Wisconsin and hold's two degrees from the Wisconsin College of Agriculture as well as a doctor's degree from Johns Hopkins University. He has been on the faculty of the Wisconsin College of Agriculture since 1897 and has been dean since 1907. He enjoys the distinction of having been a student under Pasteur in. France. He probably deserves the credit more than. any other individual for the introduction of pasteurization into the United States. His close contact with Pasteur gives him a keen insight into the personality of this noted scientist.

Category