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THE MODE OF MULTIPLICATION OF PIROPLASMA BOVIS, 
P. PITHECI IN THE CIRCULATING BLOOD COMPARED 
WITH THAT OF P. GANIS, WITH NOTES ON OTHER 
SPECIES OF PIROPLASMA. 
Plate XI and Diagrams I—IY. 
By GEORGE H. F. NUTTALL, M.D., Ph.D., Sc.D., F.R.S. 
Fellow of Magdalene College , Quick Professor of Biology in the University 
of Cambridge. 
and G. S. GRAHAM-SMITH, M.A., M.D. 
University Lecturer in Hygiene , Cambridge. 
In our last paper dealing with Piroplasma canis (Journal of Hygiene, 
April 1907, vn. pp. 232—272), we described the usual mode of 
multiplication in the circulating blood, as ascertained by a long series of 
observations on the living parasite. In summarising these observations 
we say (p. 250):— 
“ Piroplasma canis has a free and an intracorpuscular stage in the 
blood of the dog, and it is during the latter stage that multiplication 
occurs. This asexual multiplication takes place in one of the following 
ways. 
(1) A free pyriform parasite which has just left a blood corpuscle 
enters a normal corpuscle and assumes a round form, remaining quiescent 
for a time. The round body then grows and, after passing through an 
actively amoeboid stage, again becomes rounded. Two symmetrical 
processes are then protruded, which rapidly enlarge at the expense of 
the body of the parasite. Each of these processes gives rise to a mature 
pyriform parasite, which remains for a time joined to its fellow by a 
thin strand of protoplasm. On the rupture of the containing corpuscle 
these pyriform parasites become free and enter other corpuscles. 
