12 THE AMERICAN MONTHLY [Jan 
tions and have made possible many discoveries that must 
otherwise have failed. Among them may be mentioned 
the improvement of the compound microscope, the use of 
sterilized culture-fluids by Pasteur, the introduction of 
solid culture-media and the isolation methods by Koch, 
the use of the cotton plug by Schroeder and van Dusch, 
and the introduction of the anilin dyes by Weigert. It is 
interesting to note that after the discovery of the anthrax 
bacillus by Pollender and Davaine in 1849 there was a 
prolonged period during which no important pathogenic 
organisms were discovered, but during which the tech- 
nic was being elaborated. This was again followed bya 
period during which important additions followed each 
other in rapid succession. 
Thus, in 1873;Obermeier discovered the Spirillum Ob- 
ermeiri of relapsing fever. | 
In 1879, Hansen announced the discovery of bacilli in 
the cells of leprous nodules. The same year Neisser dis- 
covered the gonococcus to be specific for gonorrhoea. 
In 1880, the bacillus of typhoid feyer was first observed 
by Eberth, and independently by Koch. 
In 1880, Pasteur published his work upon ‘‘Chicken- 
cholera.” In the same year Sternberg described the 
pneumococcus, calling it the Micrococcus Pasteur. 
In 1882, Koch made himself immortal by his discovery 
of and work upon the tubercle bacillus. The same year 
Pasteur published a work upon Rouget du Porc, and Lof- 
fler and Schultz reported the discovery of the bacillus of 
glanders. 
In 1884, Koch reported the discovery of the “comma 
bacillus,’ the cause of cholera, and in the same year Loef- 
fler discovered the diphtheria bacillus,and Nicolaier the 
tetanus bacillus. 
In 1892, Canon and Pfeiffer discovered the bacillus of 
influenza. 
- In 1894,Yersin and Kitasato independently isolated the 
