20 GENERAL BACTERIOLOGY 
trihution of Cohn upon "Bacteria," the starting-point of modern 
bacterial classification. 
The diseases of man naturally attracted much attention, and in 1839 
Schoenlein examined the crusts of that disease of the scalp known as 
Favus with the microscope and found the mycelia of the fungus now 
known in his honor as i\-chorion schoenleinii. Indeed, although bac- 
teria play a prominent part in many fields of activity, the earlier 
developments of the science were almost exclusively in the domain 
of medicine. The earliest tangible relationship of bacteria to human 
infection takes its origin in a communication upon pyemia and sepsis 
by Pasteur^ in 1878. Many of the most important phenomena of 
contagion, however, were most carefully described by Oliver Wendell 
Holmes in a classical study on puerperal fever ,2 and on December 5, 
1865, Jean Antoine Villemin had announced to the French i\cademy of 
Medicine he had transmitted the "gray tubercles" from a case of human 
tuberculosis to rabbits. 
The extensive studies of Pasteur upon yeasts and the "diseases" 
of beer and wine, upon the diseases of the silk worm (pebrine and 
flacherie), upon furunculosis and puerperal sepsis,^ upon anthrax and 
anthrax immunization (attenuated viruses) chicken cholera, and some- 
what later, rabies laid broad foundations for the development of the 
science of bacteriology. 
Among the most important technical discoveries which have con- 
tributed to the development of bacteriology are: The improvement 
in the achromatic lens (about 1835) and the perfection of the substage 
condenser (Abbe) ; the use of cotton for air filters in flasks and test-tubes 
by Schroeder and von Dusch (1854), the sterilization of culture media 
by heat (Pasteur, Tyndall, Koch and others), the introduction of anilin 
dyes as staining reagents by Weigert and Ehrlich (1877), and finally, 
the use of transparent solid culture media and the plate method for 
pure cultures by Koch in 1881.* 
Sir Joseph Lister (1867) published an epoch-making contribution 
entitled, "On the Antiseptic Principle of the Practice of Surgery," in 
which is clearly set forth the importance of bacteria in surgery and the 
principles of surgical asepsis that have revolutionized this branch of 
medicine. 
In 1876 Koch^ isolated the anthrax bacillus in pure culture from the 
blood of infected animals, grew the organisms for several generations 
in the clear aqueous humor of the eye of the ox, and then reinjected 
the organisms into experimental animals and reproduced the disease. 
For the first time a specific microbe was clearly and convincingly 
' Communication to the French Academy of Sciences, April 29, 1878, Compt. rend. 
I'Acad. d. Sci., 86, 1037. 
2 Contagiousness of Puerperal Fever, New England Quart. Jour, of Med., 1843. 
^ Compt. rend. I'Acad. d. Sci., 1880, 90, 1033. 
* Mitt. a. d. Kais. Gesamte, 1881, 1, 1. 
5 Cohn's Beitrage zur Biologic der Pflanzen. 1876, Heft 2, 2, 277. 
