HISTORY OF CLASSIFICATION 95 
IV. Spirobacteria: 
Species 5. Spirillum (Ehrenberg). 
Species 6. Spirochete (Ehrenberg). 
Cohn’s classification is not used at the present time. He did not 
make any provision for pleomorphism and thus immediately opposed 
himself to Klebs, Buchner and Lister. It was about this time that 
Buchner reported the changing of B. subtilis into B. anthracis. The 
publications of Cohn and Koch proved the constancy of this char- 
acteristic and struck a forceful blow at pleomorphism. The principal 
objectors to Cohn’s classification were the medical men, but after the 
articles of Cohn and Koch they were more careful. 
Lister (1873) was one of the bitterest opponents of Cohn’s system. 
He transferred a drop of sour milk in which he had observed cocci to 
broth and observed, after a short time, long chains. He used such 
data to support his views of pleomorphism. 
De Bary (1884) divided all bacteria into two classes, those forming 
endospores and those forming arthrospores. He used spore formation 
in a different sense thari we now use it. Whenever he saw a cell which 
differed from the normal, he called it an arthrospore. His discussion 
on the formation and germination of spores is quite complete and 
interesting. 
Eisenberg (1891) for the first time attempted to use physiological 
characters. Bacteria were divided into pathogenic and non-patho- 
genic varieties. The pathogens were again divided with regard to their 
effect on man and animals. No attention was given to spore formation, 
or flagellation. 
Migula (1897) published a classification which has been generally 
used by bacteriologists. There are objections to it, but it is probably 
as good a working basis as any which is available. This is given as 
follows by Jordan (1910): 
CLASSIFICATION OF BAacTERIA—(Miauta) 
I. Cells globose in a free state, not elongating in 
any direction before division into one, two, 
or three planes..............2-00 se eee ee 1. Coccacese. 
II. Cells eylindrical, longer or shorter, and only 
dividing in one plane, and elongating to 
about twice the normal length before the 
division. 
