Gr. H. F. Nuttall and G. S. Graham-Smith 225 
experimented with the European form of canine piroplasmosis which we 
regard as an altogether milder affection than the South African. 
Nocard and Motas state that the blood of dogs suffering from the 
chronic form of piroplasmosis is less virulent than the blood taken from 
acute cases. 
(See Summary (4) on p. 227.) 
4. Records relating to the passage of P. canis through series of Dogs. 
Series I of Dogs infected during 1906, 1907. (p. 224.) 
The first dog was infected by means of ticks ( Haemaphysalis leachi, 
3 f and 8 $) received from Mr Lounsbury, Government Entomologist, 
Cape Colony. The strain was subsequently maintained by inoculation of 
blood carried on from dog to dog as indicated by the brackets connect¬ 
ing the numbers of the dogs in the left-hand column. Excepting in a 
few cases (noted in the second column) where the blood used for inocu¬ 
lation was taken from a punctured ear vein during life, the inoculations 
were made with defibrinated heart-blood injected subcutaneously. 
Series II of Dogs infected during 1908, 1909. (p. 226.) 
This series of dogs was inoculated with the same strain of P. canis 
as Series I. The strain being recovered from Sir John MacFadyean to 
whom it had been sent and who maintained it by passage from dog to 
dog in London. Dog 1, in the following series, was inoculated in London 
and its blood served to start the new series in Cambridge. 
Summary and Conclusions. 
1. Regarding attempts at immunization by means of immune serum. 
The experiments of Nocard and Motas indicated that protective 
substances occur in the blood of dogs which have recovered from 
European piroplasmosis. These authors claimed that immune serum 
destroys the parasites and that it exerts a protective and curative effect 
upon the disease. Similar experiments conducted by Robertson in Cape 
Colony gave contrary results to those of Nocard and Motas. In the 
absence of further evidence no conclusions can therefore be drawn from 
these conflicting results. Two of Robertson’s dogs which received 
injections of hyperimmune serum every day after they showed fever, 
Parasitology n 
15 
