MICROBIAL DISEASES OF MAN AND ANIMALS. 621 



of the disease in another herd in an adjoining pasture, with only a barbed 

 wire fence between. 



Haemorrhages found at autopsy constitute the most specific and char- 

 acteristic clinical evidence of this disease. Its mortality is very high, 

 running from 50 to 90 per cent. 



Haemorrhagic septicaemia of cattle, chicken cholera, swine plague, 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 Bad. bovisepticum acts as a specific causal agent for haemorrhagic 

 septicaemia of cattle. 



Body infection probably occurs by inoculation. Clinical features of 

 this disease point to inoculation and we know that the disease does not 

 spread by simple association or ordinary contact and that there is no 

 general atmospheric distribution of Bad. bovisepticum. Satisfactory 

 information concerning the period of incubation is not available. 



Acute and rapidly fatal cases where the autopsy shows only trifling 

 lesions would indicate the formation of active toxins. The characteristic 

 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 endothelial cell 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, or under the mucous membrane 

 or under serious membranes. 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 slight disturbance of temperature until 

 near death. When voluntary muscles are involved the haemorrhages 

 invade connective tissues rather than muscle tissue proper. 



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

 terium of rabbit septicaemia, B. cholera suis 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/z to i.5/z long and from 0.3 // to 0.6/1 thick. Involution forms 



