SHORT NOTE ON THE MECHANISM OF 
HAEMOLYSIS IN PIROPLASMOSIS 
CANIS 
UY 
ANTON BREINL. M.U.Dk,, 
DiRECTO*. RUSXOJtN RKSEARCH 1. ABORATORl F.S, LIVERPOOI. SCHOOI, OK 
TROPICAI. MKDICINK 
AND 
H. E. ANNETT. M.U., D.P.H., 
PROFESSOR OF COVIPARATlVIi PATHOI.OGV, fNIVKRSJTY OF 1 IVERPOOI. 
(Received for publication 6 April, 1909-^ 
For the following researches puppies and dogs of various ages 
were infected with our laboratory strain of Piroplasma canis. The 
infection was invariably fatal for young puppies up to the age of 
2 i months. After a varying incubation period, the animals shewed 
parasites in the blood in small numbers at first, but very soon a rain 
multiplication occurred and lasted for 24 to 36 hours, accompanied by 
haemoglobinuria. The urine was of a light reddish to dark mahogany 
colour, and the more rapid the multiplication of the parasites, the 
darker was the colour of the urine. Pronounced jaundice of the 
tissues was only noticed in two out of seventy animals used. In these 
young animals the blood scrum, taken at death, was of a dar le 
to mahogany colour, according to the colour of urine. 
In dogs and older puppies, the disease was hardly ever fatal. he 
parasites did not multiply so rapidly, and nearlj- always were presen 
in smaller numbers; we have never observed a pronounced 
haemoglobinuria in these animals, but for three weeks after inocu 
the serum was slightly reddish in colour. 
It was especially noticed that in young puppies a rapid d™.nu ion 
nf the blood corpuscles took place during the last few ours 
death. u kH 
It seemed, therefore, of interest to determine ^ 
destruction of the blood corpuscles was due to Isolysins or r 
With this object, the serum of infected animals m i 
the disease was added in varying dilutions to red bloo corp 
