332 
Parasite of East Coast Fever 
41 %, 47 °/o, 60 %, as is graphically shown in the chart. In both 
cases the initial rise of temperature was followed by a fall after which 
the temperature rose, fell, and rose again before falling prior to death. 
The number of infected corpuscles in the peripheral circulation in both 
cows is seen to bear no relation to the febrile reaction. 
Cow 2 was subjected to treatment by one of us (G. H. F. N.) in 
conjunction with S. Hadwen, D.V.Sci., and the case has been briefly 
mentioned in another communication as proving that Trypanblue exerts 
no effect upon the parasites, and that it is consequently unavailing in 
the treatment of East Coast Fever. The administration of Orsudan on 
the 28th day likewise exerted no beneficial effect. It will, however, be 
noted that the injection of Trypanblue on days 21, 22 and 23 (indicated 
by T, T, T, below the Chart) may have influenced the temperature and 
slightly retarded the rise in the percentage of infected corpuscles—this 
may only be due, however, to a coincidence. 
Observations upon the living parasite. 
Our studies upon the living parasite have entailed a gi’eat amount 
of labour, and our results emphasize the difference between Theileria 
parva and Piroplasma. We have made innumerable observations upon 
fresh blood in films sealed with vaseline and as quickly as possible 
placed beneath the microscope. The technique was essentially similar 
to that used by Nuttall and Graham-Smith in their studies upon 
P. cams. The majority of the parasites were observed in films 
maintained at blood temperature in Nuttall microscope-thermostats, of 
which we had four at our disposal. The time occupied in the actual 
microscopic observation and sketching of living parasites amounted to 
255’5 hours ; this time was devoted to the observation of corpuscles 
containing single parasites (88‘2 hours), two parasites (52T hours), 
three parasites (47'4 hours), four parasites (51*4 hours) and five to eight 
par-asites (16'4 hours). The average time devoted to the continuous 
observation of 41 corpuscles containing single parasites was 129 minutes, 
of 21 corpuscles with two parasites was 149 minutes, of 14 corpuscles 
with three parasites was 203 minutes, of 15 corpuscles with four parasites 
was 205 minutes, of five corpuscles with five or more parasites was 196 
minutes. Consequently, there was ample time devoted to the study of the 
living parasite. A considerable amount of the time was given to the 
observation of the largest single parasites which could be found in the 
hope that if division occurred it might the more readily be witnessed. 
