Transmission of East Coast Fever by Ticks. 327 
25. Heifer 1057 was infested on August 5, 1910, with large numbers 
of adults which had passed their nymphal stage on Cattle 829, 883, 836, 
■and 895 (Ref. No. 309) ; she was re-infested on August 19th and 29th with 
ticks of the same batch. A good many ticks were found fast the following 
day. The engorged females dropped on August 13th and 23rd, and 
September 5th, 
Bemarks. — Heifer 1057 did not contract East Coast Fever from this 
infestation. It was used later for inoculation experiments (vide article 
quoted above, Experiment 6 " B "). 
26. Heifer 1058 was infested on August 5, 1910, with large numbers 
of brown adults off Cattle 829, 883, 836, and 895 (Eef. No. 309). The 
ticks were found to be fast the following day, and large numbers of 
engorged females were collected from August 23rd. 
Bemarks. — Heifer 1058 did not contract East Coast Fever from this 
inoculation. It was used later for inoculation experiments (vide article 
cited above. Experiment 6 *' K ") finally exposed in " Burnside " and died 
of East Coast Fever. Plasma bodies were found in the blood, spleen, and 
glands on post-mortem examination. 
BesuUs. — None of the six animals which were infected with " cleaned " 
ticks developed East Coast Fever from the infestation. 
Conclusions. 
The adult ticks which as larvae had fed on sick animals, and which 
as nymphae had communicated the disease to nine susceptible cattle, or 
which had been feeding on twelve artificially immunised cattle, did not 
communicate East Coast Fever when placed in large numbers on six 
susceptible cattle. 
These observations were made on a fair number of animals and with 
a great many ticks, so that all coincidences can be excluded. 
EXPEEIMENT No. 2. 
TO SHOW THAT TICKS WHICH HAVE BEEN FEEDING ON CATTLE 
SUFFERING FROM EAST COAST FEVER DO NOT ALWAYS 
TRANSMIT THE DISEASE IN THEIR SUBSEQUENT STAGE. 
Particulars of the Ticks used. 
I. 
Ehipicephalus appendiculatus (Eef. No. 319). 
The larvae originated from mothers collected in Natal on March 18^ 
1910 ; the eggs were laid in the laboratory on March 25th and the larvae 
