[Footnote 21: Copyright, 1894, by Selmar Hess.] By Dr. CYRUS EDSON (1822-1895) [Illustration: Dr. Louis Pasteur.] Louis Pasteur, the Columbus of "the world of the infinitely little"--to quote the phrase of Professor Dumas--was born in the town of Dôle, France, on December 27, 1822. His father was an old soldier, decorated on the field of battle, who, after leaving the array, earned his bread as a tanner. In 1825 M. Pasteur moved from Dôle to the town of Arbois, on the borders of the Cuisance, where his son began his education in the communal college. The boy was exceedingly fond of fishing and of sketching, and it was not until he reached the age of fourteen that he began study in earnest. There being no professor of philosophy at Arbois, Louis Pasteur moved to Besançon, where he received the degree of _bachelier ès lettres_ and was at once appointed as one of the tutors. Here he studied the course in mathematics necessary for admission into the École Normale, in Paris, which he entered in October, 1843. Already his passion for chemistry had shown itself, and he took the lectures in that science delivered by M. Dumas at the Sorbonne, and by M. Balard at the École Normale. It was but a short time before he became a marked man in his class, especially for his intense devotion to experiment. Thanks to M. Delafosse, one of the lecturers of the École Normale, his attention was turned to crystallography, and a note from the German chemist, Mitscherlich, communicated to the Academy of Sciences, set him on fire with curiosity. Mitscherlich declared: "The paratartrate and the tartrate of soda and ammonia have the same chemical composition, the same crystalline form, the same angles, the same specific weight, the same double refraction, and the same inclination of the optic axes. Dissolved in water, their refraction is the same. But while the dissolved tartrate causes the plane of polarized light to rotate, the paratartrate exacts no such action." 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 paratartrate 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 discovered 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 inorganic and organic matter, between the absence of life and life.