C. Strickland 
245 
These observations confirm the statement by Theiler that there is 
a comparatively small decrease of the red blood corpuscles in East 
Coast Fever—there is very slight evidence of blood destruction. 
These enumerations are in marked contrast to what is observed 
in Piroplasmosis Canis. 
Thus, in 
infected, the following counts were 
K.B.C. per c.mm. 
25. II. 1911. Day 1 
4,980,000 
5 
5,056,000 
7 
4,852,000 
9 
5,040,000 
11 
4,240,000 
13 
3,130,000 
15 
2,118,000 
Piroplasma cams found in the blood 
In this disease we see that the red blood corpuscles were being 
destroyed at the rate of about half-a-million daily. 
The internal organs of cows which succumbed to East Coast Fever 
also showed little evidence that any blood destruction occurs. The 
spleen and liver were not enlarged or hyperaemic and the red bone 
marrow showed no signs of hyperplasia. The only macroscopic lesions 
observed were numerous petechial or minute haemorrhages along the 
course of the cardiac arteries in all cases. The differential blood counts 
which were carried out showed no evidence of hyperplasia of the blood- 
forming organs, i.e. there were no nucleated red corpuscles. It is well 
known that haemoglobinuria and icterus do not occur in East Coast 
Fever. Death may be due to toxaemia. 
2. Haemoglobin Estimations . 
A series of estimations of the amount of haemoglobin in the blood 
was obtained in the cases of three of the cows. 
Barcroft’s chemical method was used—the advantage claimed for 
this being that subjective errors are eliminated. The principle of the 
method consists in the reduction bv means of Potassium Ferricyanide 
of a given quantity of laked blood fully oxidised. Oxygen is given off, 
and the pressure measured on an oil manometer. It is known what 
pressure is produced by a known weight of oxidised haemoglobin and 
so the haemoglobin of any sample of blood can be estimated. 
The method is far too delicate and lengthy to take the place of 
colorimetric methods for clinical purposes, but for scientific purposes it 
gives very constant results. Two readings will seldom show a variation 
of more than 2| per cent, on the manometer. 
Parasitology vm 
16 
