cellulose into carbonic anhydride and marsh gas, which, as he showed, was due to a bacterium resembling or identical with the Bacillus amylobacter.
As might be expected, Hoppe-Seyler devoted considerable time to chlorophyll. He discovered and named the "chlorophyllan," a crystalline derivative of chlorophyll. He devised an ingenious method for showing that chlorophyll, in the sunlight, liberated oxygen in a molecular and not an atomic state. If a green plant be brought into a glass tube in water, a little putrefying blood added, and the tube hermetically sealed and placed in the dark, all oxygen is consumed and the tube shows the spectrum of hæmoglobin. If the plant be brought into the direct sunlight, the hæmoglobin is transformed by the oxygen liberated by the chlorophyll bodies into oxyhæmoglobin, which gives a characteristic spectrum. If the oxygen were liberated in an atomic state, the spectrum of methæmoglobin would appear.
Let us now glance briefly at Hoppe-Seyler's influence upon physiological chemistry. He may be called the father of this science, for, although the beginnings of biochemistry were identical with those of organic chemistry, both taking their origin in Lavoisier's experiments on oxidation, Regnault and Renard's on respiration, Chevreul's on the fats, and Liebig's and Wöhler's on urea, muscle, and animal metabolism, yet in the early half of the century the interest of the purely chemical analysis and synthesis of organic bodies had almost completely absorbed the attention of chemists. It was Hoppe-Seyler's great merit to perceive and to emphasize, with all his might, the great importance of physiological chemistry in the arts, in industries, and in medicine. His clear glance perceived that a knowledge of the chemical constitution and chemical processes of organisms in health and disease must underlie any proper treatment or understanding of disease, a fact which in the world at large to-day is becoming better and better recognized.
To further the development of this science, whose importance he perceived, he saw that it must have an undivided attention; that it must be divorced from physiology and pathology on the one hand, and from chemistry on the other, and given an independent position in the university faculty. In this contention Hoppe-Seyler met with fierce opposition in Germany, particularly from Pflüger and other physiologists and chemists, so that to-day there is but one professorship of physiological chemistry in Germany—namely, that at Strasburg. In other countries Hoppe-Seyler's idea received more favorable attention, and he lived to see such professorships established in Sweden, Norway, Switzerland, Austria, Russia, and America.
