4 i2 POPULAR SCIENCE MONTHLY 



matin particles. Dr. Williams also showed that reproduction by divi- 

 sion and by budding takes place, and she failed only to make out the 

 conjugation processes. From my own study of Dr. Williams's prepara- 

 tions, I have no doubt at all that she is right about the organism, and 

 believe that, under her name Neurorcytes, it should be grouped with the 

 rhizopod-like protozoa. 



This work on Neurorcytes is also very interesting from the side light 

 it throws on the small-pox problem. Here again, in certain phases of 

 variola, we find curious intra-cellular and intra-nuclear bodies having 

 a striking resemblance to the ordinary unstained forms of the Negri 

 bodies. These small-pox bodies were early recognized as characteristic 

 of this disease, and Guarnieri in 1892, believing they were protozoa of 

 a specific kind, named the organism Cytorcytes variola?. Perhaps the 

 majority of pathologists to-day and many biologists, are opposed to this 

 interpretation,' and these bodies, like the Negri bodies, are more com- 

 monly regarded as specific secretions or degenerations than as pro- 

 tozoa. I have no doubt myself, from long study of these small-pox 

 organisms, that they are protozoa, and believe that with fresh material 

 and by using the stain which Dr. Williams has so successfully used for 

 N eurorcytes, the last doubter will be convinced. 



At the risk of going somewhat far afield in pathological speculation, 

 let me briefly call attention to one other possibility of amoeboid organ- 

 isms and disease, viz., cancer. For years it has been known that 

 vegetable cells in ordinary edible forms, like the cabbage or turnip, etc., 

 may be stimulated to abnormal multiplication by rhizopod parasites. 

 Such a parasite — Plasmodiophora brassicce — enters the young root cells 

 of a cabbage, stimulates those cells to an unwonted degree of multi- 

 plication until great tumors are formed giving rise to the vegetable 

 disease known as 'club-root.' The plant cells become storage reser- 

 voirs of the spores of Plasmodiophora, and when the plant dies down the 

 spores are liberated in the soil. Now it has been argued that if vege- 

 table cells can be stimulated to abnormal activity, there is no real 

 biological objection to animal cells being similarly stimulated to divi- 

 sion by animal parasites, and some pathologists have gone so far even 

 as to see in certain cell inclusions of cancer peculiar bodies which they 

 compared with the Plasmodiophora spores. The comparison, however, 

 can not be sustained, and without going into the subject extensively I 

 may say in short that nothing has ever been seen in cancer cells that 

 can be interpreted as a protozoon parasite. This, however, does not 

 weigh against the parasite theory of cancer — a theory which I per- 

 sonally, believe to be the only one that satisfactorily explains the 

 disease. The organism of yellow fever has never been seen, but no 

 one doubts the parasitic nature of that disease and the fact that the 

 virus or the germs of yellow fever pass through the finest Berkefeldt 



