62 SPIROCH^ETES. 



fatal case. Recovery by crisis and subsequent relapse 

 were noted. 



Dodd found spirochaetes in certain lesions of the skin 

 in a pig, infection being conveyed by contact. The or- 

 ganisms disappeared and reappeared during the course of 

 the disease ; they did not get into the blood of the animal, 

 and inoculation was only possible in the skin. The 

 lesions in some cases healed, yet the pig died. Anaemia 

 and pneumonia were found post mortem. 



Breinl and Kinghorn noted enlargement of the spleen 

 in mice infected with Sp. laverani. This organism may 

 be the same as Sp. muris, described by Wenyon, but the 

 dimensions given by these writers are not identical, and 

 Wenyon states that Sp. muris is a harmless parasite. 

 He thinks it may be identical with Spirillum minor 

 (minus) found by Carter in the rat. 



SUMMARY OF THE PHENOMENA OF THE PATHOGENICITY 

 OF SPIROCH^ETES. 



Summarising the facts just recorded, we find that 

 there is a group of spirochaetes associated with affections 

 in which the symptoms are fever, a tendency to relapses, 

 and enlargement oj ike spleen. In this group we may 

 place the spirochaetes of the various forms of relapsing 

 fever, the spirochaetes of fowl-spirillosis, and perhaps 

 those found in the bat. In these diseases the spiro- 

 chaetes give rise to a septicaemia a generalised infection 

 in which the organisms multiply in the blood-stream 

 without the formation of any local lesion. The causal 

 connection of the spirochaetes with these affections is 

 clearly established. 



On the other hand, we have in syphilis and yaws 

 diseases in which there is a well-marked primary local 



