Page:Great Men and Famous Women Volume 6.djvu/223

DR. LOUIS PASTEUR 379 Pasteur at once instituted experiments resulting in the discovery of minute facets in the tartrate which gave it the power noted. He found in the paratar- trate these facets existed, but that there was an equal admixture of right- and left- handed crystals, and the one neutralized the effect of the other. He also discov- ered the left-handed tartrate. These discoveries at the opening of Pasteur's career brought him at once to the front among the scientific men. He followed them with a profound investigation into the symmetry and dissymmetry of atoms, and reached the conclusion that in these lay the basic difference between inor- ganic and organic matter, between the absence of life and life. Nominated at the age of thirty-two as Dean of the Faculte des Sciences, at Lille, Pasteur determined to devote a portion of his lectures to fermentation. At that time ferments were believed to be, to quote Liebig, " Nitrogenous sub- stances albumin, fibrin, casein; or the liquids which embrace them milk, blood, urine in a state of alteration which they undergo in contact with air." Pasteur examined the lactic ferment and found little rods, -^-j-Jmr mcn m length, which nipped themselves in the centre, divided into two, grew to full length and divided again, and these living things he declared to be the active principles of the ferment. He made a mixture of yeast, chalk, sugar, and water, added some of the rods, and got fermentation, He then made a mixture of sugar, water, phosphate of potash, and magnesia, and introducing fresh cells, fermentation followed.. Liebig's theory of the nitrogenous character of the ferment disap- peared when fermentation was caused in a mixture having no nitrogenous ele- ments. Pasteur had discovered that fermentation was a phenomenon of nutrition ; it followed the increase and growth of the little rods. The next step was the dis- covery of the ferment of butyric acid, a species of vibrio consisting of little rods united in chains of two or three and possessed of movement. He found these vibrios lived without air. Further experiments showed there were ferments to which air was necessary, called by Pasteur the arobies, and others to whom oxy- gen was fatal, the ancerobies. He proved, also, by an exhaustive series of experi- ments, that what is called putrefaction of animal matter is the result of the com- bined work of the cerobies and the ancerobies, which reduce that part not taken up by oxygen to dead organic matter, ready in its turn to form food for living things. His attention having been turned to the needs of the vinegar makers of Or- leans, Pasteur began the examination of the ferment which produces vinegar from wine. He found this in the mycoderm aceto, a mould-like plant which has the power of developing acetic acid from alcohol. As the result of his investi- gation, the manufacturers of vinegar in France were able to do away with the cumbrous process they had long followed, and to make vinegar, not only more cheaply, but of very much better quality. But during these experiments Pasteur found the temperature of 65 C. was sufficient to kill the mycoderm. When, then, the wine makers of France appealed to him to investigate the "diseases'" of wine, he was ready for the work.