182 PROTISTS AND DISEASE 



Syphilis and Cancer. The identity of some intracellular 

 parasitic forms in late syphilis with those of cancer has been 

 shown above in Chapter V, where the production of " cells 

 of endogenous origin " in living parasites of a late syphilitic 

 lesion is described. 



Clinical phenomena only too familiar to us express the 

 same fact in another way. 



We know that typical syphilitic differ from typical 

 cancerous lesions in certain features, but where syphilitic 

 glossitis is becoming changed into cancer these differences 

 are very gradually acquired, and it is not possible either 

 clinically or pathologically to say at what moment one 

 disease becomes converted into the other. Parasitic protists 

 are equally abundant in both, and they appear to be a series 

 of phases of the same parasite. I do not mean to say that 

 all cancer is a modified form of syphilis, but as far as can be 

 seen it is so in this particular instance. Probably cancer is 

 produced by as many different species of protists as there 

 are different bacteria, etc., that cause chronic granulomas. 



Cytoryctes Luis. I have no doubt that Cytoryctes luis 

 (Siegel 1905) is the right name for the causal parasite of 

 syphilis. This designation accords with all the facts ascer- 

 tained up to the present, and, although when Siegel invented 

 the name he does not appear to have known of my observa- 

 tions (1894), these alone would sufficiently warrant his 

 choice. 



