MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 773 



Haemorrhagic septicaemia of cattle, chicken cholera, and a number of 

 other diseases belonging to this group are very similar in clinical features 

 and the bacteria which cause these diseases are very similar in cultural 

 and microscopic features. Yet all evidence points to the fact that Bact. 

 bovisepticum acts as a specific causal agent for haemorrhagic septicaemia 

 of cattle. 



Body infection probably occurs by both inoculation and ingestion. 

 This disease does not appear to spread by simple association or ordinary 

 contact and there is no general atmospheric distribution of Bact. bovi- 

 septicum. 



Acute and rapidly fatal cases where the autopsy shows only trifling 

 lesions would indicate the formation of active toxins. The character- 

 istic haemorrhages indicate the production of substances actively toxic 

 for the endothelial cells of capillaries. The fact that these haemorrhages 

 vary in different cases from extensive subcutaneous areas to those that 

 are scarcely visible would seem to indicate that this toxin is produced 

 in greatly varying quantities or of greatly varying toxicity. 



The lesions produced by this bacterium indicate a general distribu- 

 tion through the body. 



The characteristic features as previously mentioned are the haemor- 

 rhages which are either subcutaneous, submucous or subserous. Lymph 

 glands are frequently infiltrated with extensive haemorrhages. 



Cases have been reported as showing high fever. Those studied by 

 the writer have, as- a rule, showed sHght disturbance of temperature 

 until near death. When voluntary muscles are involved the haemor- 

 rhages invade connective tissues rather than muscle tissue proper. 



Bact. bovisepticum resembles so closely the bacterium of chicken cholera, the bac- 

 terium of rabbit septicaemia, Bact. suisepticus and other members of this group {Pas- 

 teurelloses) that laboratory differentiation from other members of the group is 

 exceedingly difficult. It is a very small bacterium with rounded ends, closely 

 resembling a diplococcus. It is from i/i to 1.5^ long and from 0.3M to 0.6/* thick. 

 Involution forms sometimes appear. It shows bipolar stain, decolorizes by Gram's 

 method, produces no spores, has no flageUa, and is non-motile. 



The disease resembles anthrax in some general characteristics but 

 is easily distinguished by microscopic examination of the blood and 

 failure to find the large anthrax bacterium and by the fact that the 

 blood from the general circulation is apparently normal in haemorrhagic 

 septicaemia. This disease also resembles symptomatic anthrax (black- 



