392 BACTERlOLOaV. 



seen to retain the power of reproducing the disease for 

 a long time. The spores are tolerably resistant to the 

 influence of heat : when subjected to a temperature of 

 80° C for one hour their virulence is not affected, but 

 an exposure to 100° C. for five minutes completely 

 destroys them. They are also seen to be somewhat 

 resistant to the action of chemicals : when exposed to 

 5 per cent, carbolic acid they retain their disease-pro- 

 ducing properties for about ten hours, whereas the vege- 

 tative forms are destroyed in from three to five minutes ; 

 in corrosive sublimate solution of the strength of 

 1 : 1000 the spores are killed in two hours. 



When gelatin cultures are examined microscopically 

 the organisms are usually seen as single rods with 

 rounded ends. When cultivated in agar-agar at a 

 higher temperature spores are formed after a short 

 time ; these spores are oval, slightly flattened on their 

 sides, thicker than the bacilli, and, as stated, frequently 

 occupy a position inclining to one of the poles of the 

 bacillus, though they are as often seen in the middle. 

 The bacillus containing a spore has usually a clubbed 

 or spindle shape. 



It stains readily with the ordinary aniline dyes. It 

 is decolorized by Gram's method. Its spores may be 

 stained by the methods usually employed in spore- 

 staining. 



Pathogenesis. — When susceptible animals, especially 

 guinea-pigs, are inoculated in the deeper subcutaneous 

 cellular tissues with pure cultures of this organism, or 

 with bits of tissue from the affected area of another 

 animal dead of the disease, death ensues in from one to 

 two days. It is preceded by rise of temperature, loss of 

 appetite, and general indisposition. The seat of inocula- 



