x] BACILLI : SPECIAL 201 



guinea-pigs.^ Under the microscope it is an extremely 

 minute and thin cyHndrical rod {see Fig. 63a). 



This microbe has a much wider distribution than green 

 pus, for I have isolated it several times from the contents of 

 the intestine both in acute diarrhoea and in cholera. Dr. F. 

 W. Andrewes has made some interesting experiments with 

 the blue pigment, showing that a solution of it turns bright 

 red on the addition of acid, and it assumes again the deep 

 blue colour on adding sufficient alkah. 



I append here, as morphologically interesting forms, three 

 micro-organisms of which the position amongst bacteria is 

 not definitely determined yet. 



{a) Streptothrix. — Cohn ^ found in a concretion of the 

 human lacrymal canals long, pale, smooth, apparently 

 branched threads, either straight or twisted ; they were 

 finer than the threads of leptothrix buccalis ; he called them 

 Streptothrix Foersteri. 



{b) Cladothrix dichotoma (Zopf). — This occurs in pond- 

 water containing decomposing organic matter. It consists 

 of long whitish threads fixed on chlorophyll-containing algae. 

 The threads when fresh appear smooth, pale, occasionally 

 granular, and on staining they are seen to be composed of 

 shorter or longer bacilli, just like the leptothrix form of 

 bacillus subtilis ; but they are thicker than the bacillus 

 subtilis. Occasionally the ends of the threads are seen, not 

 as linear series of bacillar rods, but, like bacillus anthracis, 

 as chains of torula-like spherical elements. From the threads 

 single motile bacilli are seen to come off. The threads are 



' When a few divisions up to half a Pravaz syringe of the broth 

 culture is injected subcutaneously, the animals become ill and die in 

 from two to four days, showing peritonitis, pericarditis, and pleuritis, 

 with copious membranous and purulent exudation, which contains- 

 abundantly the bacilli. 



^ Beitr. z. Biol. d. PJlanzen, vol, i. p. 186. 



