z6o THE POPULAR SCIENCE MONTHLY. 



infections, septicaemia, and anthrax, or splenic fever, with, great 

 success ; and was appointed in 1880 a member in ordinary of the 

 Imperial Health Office. In 1885 he was appointed a j>rofessor, and 

 the director of the Hygienic Institute in Berlin. 



The first public report of Dr. Koch's to attract general atten- 

 tion was that in reference to the bacterium which had been found 

 associated with anthrax, or splenic disease, and was made about 

 1878. His investigations went to show that the potency of this 

 organism lay in the spores rather than in the developed bacterium. 

 He found that, when no spores were visible in the dried diseased 

 blood with which mice were inoculated, the power of conveying 

 infection lasted only for a few weeks ; while blood in which the 

 spores had separated continued virulent for at least four years. 



He next turned his attention to those infectious disorders 

 which originate in the introduction of poisonous matter through 

 wounds. Living organisms had already been observed in these 

 diseases, but their connection with the development of the infec- 

 tion had not been determined. Dr. Koch's experiments with 

 small animals showed that different forms of disease were pro- 

 duced by the injection of putrid blood, one of which was not 

 accompanied by the development of bacteria, but seemed due to a 

 special poison which he named septin or sepsin, while another 

 form was evidently bacterial; and that the effects varied with 

 different animals. 



In 1882 Dr. Koch published the results of experiments which 

 went to confirm the opinion already held by physicians who had 

 observed the progress of the discovery of the fungoid origin of 

 various infections, that tubercular disease was also caused by 

 microphytic germs. He claimed not only that he had ascertained 

 the bacterial origin of the disease, but to have detected the specific 

 microbe, having found a characteristic and previously unknown 

 bacillus in all tubercularly altered organs. He had observed it in 

 pulmonary tuberculosis, cheesy bronchitis and pneumonia, tuber- 

 cles of the brain, intestinal tubercles, scrofulous glands, and fun- 

 gous inflammation of the joints ; in all cases which he had exam- 

 ined of spontaneous consumption in animals in cattle, hogs, 

 poultry, monkeys, porpoises, and rabbits. In monkeys dead of 

 consumption he had found the organisms in quanities pervading 

 the lungs, spleen, liver, diaphragm, and lymphatic glands. He 

 supposed that, escaping into the air from the expectorations of 

 phthisical patients, they were inhaled into the lungs, where they 

 developed. "Whenever the tubercular process was in its early and 

 active stage, they were present in great numbers. When the 

 climax of the tubercular eruption was passed, they decreased and 

 might totally disappear. 



Dr. Koch's report of this investigation was published in one of 



