396 



MALIGNANT CEDEMA. 



■i 



followed by a peptonising process which advances so that the 

 whole of the medium becomes converted into a muddy-coloured 



whey that gives off a heavy 

 putrid odour. 



Spore formation occurs 

 above 20° C, and is usu- 

 ally 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 Inocu- 

 lation. — A considerable 

 number of animals — the 

 guinea-pig, rabbit, sheep, 

 and goat, for example — 

 are susceptible to inocula- 

 tion with this organism. 

 The ox is said to be quite 

 immune to experimental 

 inoculation, 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 inflammatory oedema around 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 in- 

 volved. These parts have a very putrid odour. The internal 

 organs are congested, the spleen soft but not much enlarged. 

 In such conditions the bacillus of malignant oedema, both in 

 short and long forms, will be found in the affected tissues along 

 with various other organisms. Spores may be present, espe- 



V-7 



ABC 



Fig. 134. — Stab-cultures in agar, five days' growth 

 at 37° C. Natural size. 



A. Tetanus bacillus. E. Bacillus of malignant cedema. 

 C. Bacillus of quarter-evil (Rauschbrand). 



