326 
Parasite of East Coast Fever 
in the blood “ only towards the end of the fever reaction in East Coast 
Fever,” being previously latent in the animals which had been “salted” 
against Redwater. He distinguished “ two groups of piroplasmosis,” 
the inoculable (Redwater, canine and equine piroplasmosis) and the 
uninoculable (East Coast Fever) by injection of infected blood. The 
parasites in the latter are much smaller than in the former. He named 
the parasites of East Coast Fever Piroplasma parvuvi. Theiler 
distinguished the parasite of East Coast Fever from P. bovis because of 
the frequent occurrence of bacillary forms and the minute size of the 
parasite, but he nevertheless retained the new parasite in the genus 
Piroplasma. 
The fact that East Coast Fever is not communicable by inoculations 
with large quantities of blood containing great numbers of the parasites 
led to other modes of inoculation being attempted. Thus, Koch and his 
collaborators inoculated splenic pulp and material obtained from lym¬ 
phatic glands both subcutaneously and intravenously, but they obtained 
negative results. Theiler and Stockman (personal communication) and 
Nuttall (spleen pulp inoculated subcutaneously, unpublished) have also 
obtained negative results from similar inoculations. Meyer, of Pretoria 
(September, 1909), has, on the other hand, recently succeeded twice in 
transmitting East Coast Fever to cattle by intraperitoneal inoculations 
made by transplanting the whole spleen or portions of spleen removed 
from animals killed whilst dying from the disease. 
We shall take occasion, in a future paper, to discuss the systematic 
position of the Haemocytozoa which are usually ranged under the genus 
Piroplasma. Nuttall and Graham-Smith (1906, p. 645) have laid 
stress upon the differences existing between P. bovis and the parasites 
of East Coast Fever both as to morphology and pathogenicity, and 
Bettencourt, Franca and Borges (1907) founded a new genus Theileria 
to include similar parasites to those of East Coast Fever. One of us 
(Nuttall, ix. 1908, p. 516) has expressed himself in complete agreement 
with the Portuguese authors in the matter of naming the parasite of 
East Coast Fever Theileria parva. 
From a study of three typical species of Piroplasma (P. canis, 
P. bovis, and P. pithed), Nuttall and Graham-Smith (1908, p. 141) 
concluded that the members of the genus Piroplasma may be dis¬ 
tinguished from other intracorpuscular parasites by the fact of their 
commonly occurring in the form of paired pyriform bodies and less often 
in groups of four, eight, etc. within the infected corpuscles. The pyriform 
bodies arise by a peculiar budding process which they were the first to 
