300 BACILLI PATHOGENIC IN ANIMALS. 



considerable numbers when the post-mortem examination 

 is not made immediately after death. Inoculation 

 with the organs or the serous fluid from the tumours 

 causes the same or similar phenomena and a fatal 

 result, in calves, sheep, goats, rabbits, and guinea- 

 pigs ; horses, asses, and white rats are but little 

 <\ susceptible; swine, dogs, cats, ordinary 

 \ f ra ^s, and fowls are completely immune. 

 & ^ In the case of guinea-pigs, the sub- 

 Fig. 84. Eausch- cutaneous injection of the serous fluid 

 aspore b bearin at causes an extensive cedema of the sub- 

 cutaneous tissue ; the animal dies after 

 two or three days, and then it is found that the sub- 

 cutaneous tissue is infiltrated with a large amount of 

 sero- sanguineous fluid, and that the muscles are 

 discoloured. If too small a quantity is injected, only a 

 local tumour is formed in the animal inoculated, and 

 this tumour heals and leaves the animal immune against 

 larger doses. 



Morphological The bacilli are 3 to 5 /i. in length, *5 to "6 /x. in 

 the^bacilli. breadth, with distinct spontaneous movement, and thus 

 at once distinguished from the anthrax bacilli. They 

 often show at one end a round swelling, so that their 

 form resembles that of the clapper of a bell, and in this 

 swelling an oval refracting spore, exceeding the rod in 

 diameter, is gradually formed. 



Cultivations. Arloing, Cornevin, and Thomas were able to cultivate 

 the bacilli, but only by the exclusion of oxygen. The 

 organisms grow best in fowl-broth, to which a little 

 glycerine and sulphate of iron have been added, the 

 vessels employed being exhausted of air, or filled with 

 carbonic acid. In cultivations in other nutrient media 

 the virulence of the organisms diminishes very rapidly. 

 Artificial The same observers were also able to obtain an artificial 



the e rausch^ f attenuation of the rauschbrand bacilli by another method, 

 brand bacilli, and on inoculation of these attenuated bacilli they were 

 inoculation/ able to produce immunity of the animals against the 

 virulent bacilli. They found in the first place that local 

 affections, which left immunity behind, arose after sub- 

 cutaneous inoculation of small quantities of the serous 



