420 Treatment of Canine Piroplasmosis 
which had been successfully treated, succumbed to distemper, the four 
referred to escaped this intercurrent disease or (Dog 6) recovered from 
it. The following data refer to these four dogs whose previous history is 
in each case briefly summarized so as to render the subsequent record 
more intelligible. 
Except for Dog 4, which is showing increasing signs of advancing 
age, all of the animals are at present healthy as far as outward appearances 
are concerned 1 . The body temperature has remained normal in the 
cases of Dogs 1 and 3 and in the cases of Dogs 4 and 6 has shown 
occasional slight rises which may have been due to other causes. The 
body-weight has increased in all cases: from 15 to 17 lbs. (232nd 
day, Dog 1), from 17^- to 21 lbs. (235th day, Dog 3), from 20 to 25 lbs. 
(227th day, Old Dog 4), and from 16 to 20 lbs. (210th day, Dog 6). 
Parasites have not again been detected in the peripheral blood upon 
microscopic examination. 
On the other hand, the parasites must have persisted in the animals, 
for blood taken from the ear-veins of the four dogs gave rise to fatal 
piroplasmosis in all of the test dogs which were inoculated with it. 
Thus: 
The blood of 
Day after inoculation of 
Treated Dog when its 
No. of Test 
No. of days after inocula¬ 
tion when Test Dog 
Treated Dog No. 
blood was collected 
Dog inoculated 
died of piroplasmosis 
1 
143 
I 
19 
3 
190 
II 
16 
4 
182 
III 
13 
6 
165 
IV 
21 
6 
210 
V 
34 
It is obvious from the foregoing that the treated dogs behave, in 
respect to the survival of the parasites in their blood, similarly to 
animals which recover under natural conditions. They represent 
“salted” animals in which parasites persist for an indefinite time 
without apparently producing any ill effects, the number of parasites 
present in the blood being exceedingly small. Although the test dogs 
which were inoculated with the blood of the recovered animals lived 
somewhat longer than is usual after inoculation with the blood from 
acute cases of piroplasmosis, there is no evidence that the parasites in 
the blood of the recovered animals had in any way become attenuated. 
Two of the recovered dogs were, moreover, reinoculated with virulent 
blood, but neither of them showed any reaction. Dog 3 was reinoculated 
on the 221st day after the first inoculation, and Dog 4 was similarly 
reinoculated on the 213th day. 
1 Dog 6 has died since this was written, see protocol p. 422. It was killed by fighting 
with another dog on the 236th day after inoculation. 
