BACILLUS MYCOIDES. 403 



faction extends very gradually over the whole surface, and 

 affects an upper zone of constantly increasing depth. 

 This organism was found by Praussnitz as an accidental 

 contamination ; it is rare. 



Bacillus mycoides. 

 (Earth bacillus.) 



These are fairly thick mohile bacilli approaching in Earth bacillus 

 size the anthrax bacilli, and often forming long pseudo- mc 

 threads. In the threads oval, highly refracting spores 

 appear at regular intervals, and this is also the case in 

 the individual bacilli ; the spore lies about the middle 

 of the bacillus. In gelatine plates a whitish turbidity is 

 formed in which fine whitish threads of irregular inter- 

 woven and branched appearance are seen. This net- 

 work of threads attains, even after 12 to 20 hours, an 

 extent of about 10 mm., and resembles the mycelium of 

 a fungus so much that one may be in doubt whether it 

 is that, or whether it is a colony of bacteria. The threads 

 remain delicate and fine so long as they lie in the depth 

 of the gelatine, but they increase markedly in breadth and 

 lose their sharp outlines when they reach the surface. 

 The individual colonies soon run together as the result of 

 the growth of this network of threads. Under a low 

 power the threads are seen to be composed of bundles of 

 bacilli, which usually lie loosely beside each other, but 

 are at times densely matted together, and have on the 

 whole a very curved and convoluted course. When the 

 threads reach the surface liquefaction of the gelatine 

 occurs in the uppermost layer, which has already become 

 diffusely opaque as the result of the growth of the 

 colonies. In puncture cultivations minute hairs spread 

 in the first place from the line of puncture into the 

 gelatine in dense rows ; later the accompanying lique- 

 faction obscures the characteristic growth. On potatoes 

 a whitish tenacious layer is formed which slowly extends 

 over the surface. These bacilli are almost always pre- 

 sent in specimens of earth taken from the surface of 



