298 H. B. FANTHAM. 



forms showed the pi'csence of more thau one " nucleus " or 

 chromatin mass. This feature of "nuclear dimorphism" is 

 of great interest at present in elucidating the probable close 

 affinities of the Hicmosporidia and Has mo flagellates. 



As is well known, the micro-organism Piroplasraa 

 bigeminum (Babesia bovis) is the pathogenic agent of 

 Texas Fever (Red-water) in cattle. The preparation exa- 

 mined and now described was a blood-smear, made imme- 

 diately after the death of the Bovine, labelled " scraping 

 from hoart-mnsclo," and came from Australia. There have 

 been serious ravages among cattle in Queensland, due to 

 Red-water. A few other preparations of the parasite were 

 also examined. 



In this particular blood-film from heart-muscle about 90 

 per cent, of the red corpuscles were infected, one corpuscle 

 usually containing two pyriform parasites, especially charac- 

 teristic of this, the type-species of Piroplasma, and which 

 led to the specific name bigeminum (Smith and Kilborne). 



All members of the genus Piroplasma are small, usually 

 occurring in pairs inside various mammalian erythrocytes, so 

 that the diameter of the host-cells only averages 7 ^, and the 

 parasite is considerably smaller, about 3^ by I'h fx. The 

 minute character of the parasite has been a source of great 

 difficulty in the present research. Great care has been 

 necessary with the illumination, and high magnifications have 

 been used. 



For the photo-micrographs, from which the figures in Plate 

 18 were drawn, I am greatly indebted to Dr. N. H. Alcock, 

 Lecturer on Physiology at St. Mary's Hospital Medical 

 School, assisted by Mr. G. R. Lynch. To these gentlemen 

 I would tender my best thanks for the trouble they have 

 taken in photographing this exceedingly difficult object. 

 Since it was found that the photo-micrographs, which clearly 

 exhibited the "nuclear dimorpliism " in question, were too 

 delicate to sustain clear reproduction in the number of copies 

 required for circulation, the photographs have been divvwn 

 (twice the size of the original) by the lithographic artist. 



