EDITORIAL. 107 



At the time Koch commenced his investigations in the early 

 seventies, Pasteur had ah-eady corrected the mistaken idea of spon- 

 taneous generation of microbes, and had published epoch-making 

 researches which through Lord Lister had been applied in the anti- 

 septic treatment of wounds; but the road had been but partly opened, 

 the connection between bacteria and infectious diseases still beinor 

 obscure, and it remained to be determined whether the bacteria 

 found in certain diseases were causative or merely consequential 

 agents. 



While practicing in the country, Koch carried on investigations 

 with anthrax and traumatic infective diseases. Although the etiologic 

 significance of the anthrax bacillus had previously been demonstrated 

 by Davaine, it remained for Koch to determine the conditions under 

 which spores are formed and the part that they play in the spread of 

 the disease in nature. Five years later he published valuable re- 

 searches relating to the resistance of anthrax spores to heat and 

 chemical agents. This work in 1876 and the appearance in 1878 of 

 his monograph on researches in the etiology of traumatic infective 

 diseases marked the definite beginning of exact bacteriologic-etiologic 

 investigation. 



Koch's work in Berlin in 1880 is said to have begun in a small 

 room with one window, with Loeffler and Gaffky as assistants. Here 

 the investigations of anthrax were continued and photomicrography 

 and new culture methods, including the perfection of the transparent 

 solid media, were worked out. In the introduction of the so-called 

 plate method of obtaining pure cultures of bacteria, an invaluable 

 means was furnished by which a single bacterial species or strain 

 could be isolated from a mixture of many. It was a most important 

 advance in bacteriological technique. In 1880, simultaneously with 

 Eberth, but independent of him, he discovered the typhoid bacillus. 



On March 2-1, 1882, Koch startled the world by announcing the 

 discovery of the tubercle bacillus as the cause of the dread disease 

 tuberculosis. He demonstrated the presence of the tubercle bacillus 

 in the diseased tissue of tuberculous animals and in the sputum and 

 tissues of human beings suffering from the disease. His ingenuity 

 and mastery of methods enabled him to stain the organism in the 

 tissues and to isolate and study it on artificial media outside the 

 body — a task which many others had attempted but failed to accom- 

 plish. 



He continued his investigations on tuberculosis as opportunity 

 offered, and in 1901 announced his conclusion that human and bovine 

 tuberculosis are due to different types or strains of the bacillus, as 

 pointed out by Theobald Smith, But he went further, holding the 

 view that bovine tuberculosis is of minor importance in the develop- 



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