210 
Theileria parva 
answered Miyajima’s description of “ ordinary bouillon ” (meat extract, 
peptone 1 °/ 0 , NaCl '5 °/ 0 ). The sodium citrate was used in 2 °/ 0 solution 
in physiological salt solution ('8 °/ 0 ). The NaCl solution was '8°/ 0 . The 
cow died of East Coast Fever on 13. ill. 1909, that is, a week after the 
blood was withdrawn for cultural purposes. 
The cultures were examined at various intervals of time in unstained 
and stained preparations made from the surface layer of corpuscles and 
leucocytes which had gravitated to the bottom of the vessels. 
Exp. II. In this experiment 24 ticks, of the same lot as in Experi¬ 
ment I, were placed on a cow on 6—-11. iv. 1909. On 25. iv. the 
parasites were detected for the first time in the cow’s blood. On 26. IY. 
an enumeration showed that 6 % of the corpuscles harboured parasites. 
Venous blood was now collected in the same way as in the previous 
experiment. The cow died of East Coast Fever on 5. v. 1909. 
The cultures were examined both fresh and stained. They were 
prepared as follows : (a) blood and bouillon as in experiment I, ( b ) 
blood and ’8°/ 0 NaCl solution mixed in the proportion 1:1 or 2:1, 
(c) blood and 4°/o citrate mixed in the proportion 5:1. The results 
agreed entirely with those detailed under Experiment I. 
Conclusions. 
Our observations do not confirm those of Miyajima, since we never 
saw any development of Theileria parva in cultures. We have seen 
degenerated leucocytes assume various shapes which at times agreed in 
appearance with that of some of the developmental forms described by 
Miyajima. We conclude that the flagellates described by Miyajima as 
occurring in cultures of cattle blood containing Th. parva were probably 
cultural forms of a Trypanosoma which he failed to detect in blood 
smears taken from animals because of their small numbers in the 
circulating blood. Although we are at present only able to report 
upon two experiments, owing to our limited facilities for keeping cattle 
in the laboratories at Cambridge, we consider that they sufficiently 
indicate the need of caution in accepting Miyajima’s results until further 
experiments are forthcoming. 
