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THE DEGENERATIVE APPEARANCES OBSERVED IN 
PIROPLASMA CANIS AND IN TRYPANOSOMA 
BRUGEI FOLLOWING UPON DRUG TREATMENT. 
By GEORGE H. F. NUTTALL, F.R.S. 
(2 Diagrams.) 
In a lecture delivered recently in Cambridge, I had occasion to 
demonstrate the degenerative changes undergone by P. canis and 
Tr. brucei in the blood of animals which had been subjected to curative 
treatment with drugs. These changes have not as yet been depicted. 
They are, in my opinion, of more than passing interest, since they may 
help us to distinguish normal from abnormal parasites in untreated 
animals. Without doubt there occurs a certain death-rate amongst 
blood parasites under natural conditions; what this death-rate is we do 
not know, but appearances which cannot be regarded otherwise than as 
degenerative are not infrequently encountered. On the other hand, there 
is always a danger that false interpretations may be placed upon abnormal 
or degenerative forms, and of this I fear there is ample evidence in 
current literature. In publishing this note I merely desire to draw 
attention to what may prove to be a useful method of differentiating 
some of the normal from the abnormal appearances presented by 
Haematozoa. 
I. The degeneration observed in Piroplasma consequent upon 
Trypanblue treatment. 
In our papers on the successful drug treatment of canine and bovine 
piroplasmosis (. Parasitology , vol. II. 1909, Nuttall and Hadwen, 
pp. 163,190, 249, 265; Nuttall, pp. 418, 432) we described how P. canis 
and P. bovis degenerated under the influence of trypanblue, the appear¬ 
ances observed in both species of parasites being similar. To repeat, 
