Microbic Diseases Individually Considered. 185 



dissociated by shaking. They slowly increase in size, 

 still remaining united; they are formed of filaments 

 of great length intwined with each other like the 

 threads of cotton wadding. After a certain time 

 these filaments produce spores and break up ; the lib- 

 erated spores fall to the bottom of the vessel where 

 they look like fine sand. 



Inoculated to gelatin by puncture, the charbon bacillus 

 forms a culture no less characteristic; along the deep 

 track a white line appears from which project hori- 

 zontally ramifying branches, so that the whole simu- 

 lates the branch of a tree with its divisions and sub- 

 divisions ; on the surface a white layer is formed 

 which slowly fluidifies the gelatin and gradually in- 

 creases in thickness. 



The colonies which develop on gelatin plates are 

 formed of tufts of interlacing filaments showing ar- 

 borescent prolongations at their periphery. 



On agar the bacteridium grows as upon gelatin.* 



On potato it produces a dry crust of a white color. 



Virulent cultures contain various toxic substances: 

 a toxalbuminoid, precipitated by alcohol (Nankin, 

 J3rieger, Fraenkel), and an alkaloid (Martin). 



Research and coloration. — The charbon bacillus is 

 found in the blood of animals which have died from 

 the disease, and in the local oedema consecutive to ac- 

 cidental or experimental inoculation. It is easily 

 recognized in fresh unstained blood preparations in 

 the form of very clear articulated or non-articulated 

 rods, lying motionless between the corpuscles. It 



* [But the growth in agar tubes is in no way characteristic. — D.] 



16 



