VECTOR OF CANINE PIROPLASMOSIS DUE TO P. GIBSONI           361

present experiments, only two dogs provided the infective feed to the larval ticks,
as shown in the following Table :—

Ticks

Dog
No.

Number of
larvæ
used

Number
of larvæ
recovered

Duration
of larval
feed

Average body
temperature and
condition of blood
of host during
larval feed

Remarks

Lot A .

239

200-300 .

All .

4 days .

102.3°F. . A few
P. gibsoni. Anæmia.

„ B .

239

About 100

All .

5 „ .

102°F. Rare
P. gibsoni. Marked
anæmia.

„ C .

239

500-600 .

All .

6 „ .

102°F. A few
P. gibsoni. Marked
anæmia.

„ D .

240

200-300 .

All .

5 „ .

102.9oF. Very rare
P. gibsoni. Slight
anæmia.

„ E

240

500-600 .

About 100*

4 „ .

101.5°F. Fairly fre-
quent to rare
P. gibsoni. Marked
anæmia.

*Cloth-cover
found detached,
apparently due
to insufficient
adhesive.

„ F .

240

About 300

All† .

6 „ .

101.7°F. A few to
rare P. gibsoni.
Marked anæmia.

†Only about 20
larvæ found
alive; others
had fed, but
were found
dead, presum-
ably owing to
an extension of
adhesive to
centre of cloth-
cover.

The temperature shown in each case in the foregoing table represents the
average of the readings taken both in the morning and in the evening during the
full period of the infective feed of the ticks and has been inserted in the table
merely with the object of completing the protocols of the dogs concerned, for, as
already mentioned, the occurrence of febrile symptoms was not found to be a
certain indication of the development of the infection, so that no animal was
regarded as definitely infected until the appearance of a fair number of parasites
in the circulation, associated with varying degrees of anæmic changes, and as will
be seen from the table the larvæ were infected from such dogs as showed these two
symptoms of the disease, except in the case of lots B and D, which, in the absence

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