CHARACTERS OF BACILLUS. 371 



of growth at the bottom. At the same time bubbles of gas 

 are given off, which may split up the gelatine. The colonies 

 in gelatine plates under anaerobic conditions appear first as 

 small whitish points which under the microscope show a 

 radiating appearance at the periphery, resembling the colonies 

 of the bacillus subtilis. Soon, however, a sphere of lique- 

 faction occurs in which the growth forms an irregular mass, 

 though a narrow zone with radiate striation may sometimes 

 be seen at the margin of the sphere ; gas is developed 

 around the colonies. 



In deep tubes of glucose agar at 37 C., growth is ex- 

 tremely rapid. Along the line of puncture, growth appears 

 as a somewhat broad white line with lateral projections 

 here and there. The medium is quickly cracked in various 

 directions by the evolution of gas, and may be pushed 

 upwards so high as to displace the cotton -wool plug. 

 The cultures possess a peculiar heavy, though not putrid, 

 odour. 



Spore formation occurs above 20 C., and is usually 

 well seen within forty- eight hours at 37 C. The spores 

 have the usual high powers of resistance, and may be kept 

 for months in the dried condition without being killed. 



Experimental Inoculation. A considerable number of 

 animals the guinea-pig, rabbit, sheep, and goat, for ex- 

 ample are susceptible to inoculation with this organism. 

 The ox is said to be quite immune to experimental inocu- 

 lation, though it can, under certain conditions, contract 

 the disease by natural channels. The guinea-pig is the 

 animal most convenient for experimental inoculation. When 

 the disease is set up in the guinea-pig by subcutaneous 

 inoculation with garden soil, death usually occurs in about 

 twenty-four to forty-eight hours. There is an intense inflam- 

 matory oedema from the site of inoculation, which extends 

 over the wall of the abdomen and thorax. The skin and 

 subcutaneous tissue are infiltrated with a reddish-brown fluid 

 and softened ; they contain bubbles of gas and are at places 

 gangrenous. The superficial muscles are also involved. 

 These parts have a very putrid odour. The internal 



