Tixuisminsion of East Coast Fever by Ticks. 
321 
27, 1910, the larvte were placed on Calf 917. (Calf 917 contracted East 
Coast Fever from the ticks of Calf 700 — vide sub-head {h).) The larvae 
were collected off Calf 917 between April 11 and 14, 1910, at a time when 
Theileria parva were frequently met with in the blood and the plasma 
bodies were present in the organs. 
Cleaning the Ticks. — The engorged larvae moulted in due time, together 
with nymphye off Cattle 700 (Ref. No. 309) and off 923 (Ref. No. 268) were 
used for the infestation of the following eight cattle : Nos. 561, 908, 919, 
1101, 914, 1012, 1026, and 1040. 
(c) Rhipicephalus appendiculatus (Ref. Nos. 309, 268, and 335). 
1. Heifer 561 was infected on July 26, 1910, with brown nymphge as 
above, and developed East Coast Fever after an incubation period of 
12 days. This heifer was killed for experimental purposes 10 days later, 
when microscopical examination proved the presence of Tli. parva in the 
blood and the plasma bodies in the glands. 
Remarks. — The ticks which as larvae had fed on Cattle 700, 917, and 
923, proved virulent in their nymphal stage for Heifer 561. 
Note. — The engorged brown nymphae were all collected by August 2, 
1910. They moulted iato adults on September 19, 1910, and were placed 
on Heifer 1088 on December 15, 1910, and on Calf 1145 on January 6, 
1911 (vide Experiment 1 " C," Nos. 23 and 24). 
2. Heifer 908 was infested on July 26, 1910, with brown nymphae off 
Cattle 700, 923, and 917 (Ref. Nos. 309, 268, and 355), as above. This 
heifer developed East Coast Fever after an incubation time of 13 days, and 
was killed for experimental purposes on August 22, 1910, after an illness 
of 14 days. The blood contained Th. parva, and in the glands and spleen 
plasma granules were frequently found. 
Note. — The engorged brown nymphae were collected by August 2, 1910, 
and had moulted into adults on September 19, 1910 ; the adults were 
placed on Heifer 1088 on December 15, 1910, and on Calf 1145 on 
January 6, 1911, in order to test their infectivity (vide later Experiment 
No. 1 " C," Nos. 23 and 24). 
3. Calf 919 was infested on June 27, 1910, with brown nymphae off 
Cattle 700, 917, and 923 (Ref. Nos. 309, 335, and 268), as above. An East 
Coast Fever reaction set in after an incubation time of 14 days, and the 
calf died on July 28, 1910, the 16th day of illness. The blood contained 
Th. parva in large numbers, and plasma bodies were frequently met with 
in the glands. 
Note. — The engorged brown nymphae w^ere all collected by July 12, 
1910, and moulted into adults in due time, when they were placed on 
