508 H. B. FANTHAM. 



Graham-Smith (15) has recently (October, 1905) recorded 

 an intra-corpuscular parasite from the erythrocytes of moles. 

 Although at first thought to be piroplasma-like, yet apparently 

 the parasites do not belong to the genus Pi r op 1 asm a, 

 according to their discoverer, but are "longer or shorter rods 

 of irregular shape " occasionally even devoid of chromatin. 

 Graham-Smith does not appear to have named them yet. 



It is interesting to note that a rodent, Sperm op hilus 

 Columbian us, is said to be concerned in the spread of human 

 tick fever in the Rocky Mountains. Wilson and Chowning 

 (50) give reasons for thinking that this Spermophilus is a 

 third host of Piroplasma hominis, and consider that it 

 is really the normal or true host of the parasite. In the 

 Columbian Spermophile the P. hominis is non-pathogenic, 

 and the human subject would seem to be not the true host 

 but one in which the parasite lives with, perhaps, some diffi- 

 culty, and wherein it consequently sets up pathogenic reac- 

 tions resulting in human '' spotted " or " tick fever." With 

 this may be compared the action of Trypanosoma brucei, 

 which is non-pathogenic in the " wild game " of South Africa, 

 its true hosts, but is pathogenic or hurtful to the imported 

 horses not indigenous to the country; similarly T. lewisi is 

 non-pathogenic in the rat, which is apparently its true or 

 natural host. 



VII. Summary of Results. 



The parasite described in this memoir occurs in the blood 

 and certain organs, as the liver, spleen, kidneys, lung, heart- 

 muscle, and boue-marrow of white rats, three of which came 

 under my observation, but only one of them lived long enough 

 to allow of continued study, and that only for a comparatively 

 short time, too short to allow of observation on the methods 

 of cross-infection. 



The parasites are intra-corpuscular in habitat, occurring in 

 the erythrocytes or haematids of the host, and belong to the 



