HISTORICAL. v4 
In 1873 Obermeier, a German physician, announced the discov- 
ery, in the blood of patients suffering from relapsing fever, of a mi- 
nute, spiral, actively motile microérganism—the Spirochete Ober- 
meieri—which is now generally recognized as the specific infectious 
agent in this disease. 
The very important work of Koch upon traumatic infectious 
diseases was published in 1878. 
In 1879 Hansen reported the discovery of bacilli in the cells of 
leprous tubercles, and subsequent researches have shown that this 
bacillus is constantly associated with leprosy and presumably bears 
an etiological relation to the disease. 
In the same year (1879) Neisser discovered the ‘‘ gonococcus ” in 
gonorrhceal pus. 
The bacillus of typhoid fever was first observed by Eberth, and 
independently by Koch, in 1880, but it was not until 1884 that Gaff- 
ky’s important researches relating to this bacillus were published. 
In 1880 Pasteur published his memoir upon fowl cholera, and the 
same year appeared several important communications from this 
pioneer in bacteriological research upon the “‘ attenuation” of the 
virus of anthrax and of fowl cholera and upon protective inocula- 
tions in these diseases. 
In 1880 the present writer discovered a pathogenic micrococcus, 
which he subsequently named Micrococcus Pasteurt, and which is 
now generally recognized as the usual agent in the production of 
acute croupous pneumonia—commonly spoken of as the ‘‘ diplococ- 
cus pneumoniz,” but described in the present volume under the 
name of Micrococcus pneumonice croupose. 
In 1881 several important papers by Koch and his colleagues ap- 
peared in the first volume of the ‘‘ Mittheilungen ” published by the 
Imperial Board of Health of Germany. 
The following year (1882) Koch published his discovery of the 
tubercle bacillus. 
The same year Pasteur published his researches upon the disease 
of swine, known in France as rouget. 
The same investigator (Pasteur) also published in 1882 his first 
communication upon the subject of rabies. 
Another important discovery was made in 1882 by the German 
physicians Léffler and Schiitz, viz., that of the bacillus of glan- 
ders. 
Koch published his discovery of the cholera spirillum—‘‘ comma 
bacillus ”—in 1884. 
The same year (188+) Loffler discovered the diphtheria bacillus. 
Another important publication during the same year was that of 
Rosenbach, who, by the application of Koch’s methods, fixed defi- 
