478 BACTERIOLOGY. 



10 animals, and Koch 5 out of 15 animals so treated 

 to die. 



In 1885, 1886, and 1887 Franck^ examined seven 

 cases that clinically presented the condition of cholera 

 nostras; in none of these seven cases \vas the organism 

 of Finkler and Prior, which they claimed to be the 

 cause of the disease, found. In all cases the results of 

 bacteriological examination, in so far as the constant 

 presence of an organism that might stand in causal 

 relation to the disease was concerned, were negative. 

 Only the ordinary intestinal bacteria were detected. 



spirillum tyrogenum (chbesb spirillum of 

 deneke). 



Another spiral form, likewise forming short, comma- 

 shaped segments in the course of its growth (Fig. 82), 

 is that found by Deneke in old cheese. It is a little 

 smaller than Koch's spirillum. It is motile and has 

 but a single flagellum, attached to one of its ends. It 

 liquefies gelatin more rapidly than does Koch's organ- 

 ism. It possesses no characteristic grouping, as can be 

 seen in impression cover-slips of its colonies. It does 

 not form spores. On gelatin plates its colonies develop 

 very rapidly as saucer-shaped depressions ; after twenty- 

 four hours they vary from 1 to 4 mm. in transverse 

 diameter. To the naked eye they are almost trans- 

 parent, and are usually marked by a denser centre and 

 peripheral zone, the space between being quite clear. 

 They are not regularly round in all cases. A peculiar 

 aromatic odor accompanies their growth on gelatin. 

 Under low magnifying poAver the smallest colonies are 

 irregularly round in outline, their borders being often 



1 Zeitschrift fur Hygiene, 1888, Band iv. S. 207. 



