336 
Transactions of the Boyal Society of South Africa. 
EXPEKIMENT No. 3. 
TO NOTE WHETHER BROWN ADULTS WHICH WERE FEEDING AS LARV^ 
ON CATTLE SUFFERING FROM EAST COAST FEVER, AND WHICH 
PROVED TO BE VIRULENT AS NYMPHS, WILL TRANSMIT THE 
DISEASE TO ADULTS AFTER HAVING PASSED THEIR NYMPHAL 
STAGE ON A RABBIT. 
Particulars of the Ticks. 
1. Ehipicephalus appendiculatus (Ref. No. 342). 
The larvae originated from mothers collected in Natal on January 12, 
1910 ; the eggs were laid on January 18th, and the larvae hatched on 
February 18, 1910, and were placed on 923 on March 20, 1910 (Ref. 
No. 268), at a time when the parasites of East Coast Fever were fre- 
jquently noted in the blood. The engorged larvae were collected on March 
23, 1910, and hatched out in due time. One lot was placed on Cow 596 
on April 7, 1910, and transmitted the disease {vide Experiment No. 1 (a) ). 
A second lot was placed on a rabbit, and the engorged nymphae were 
collected from April 13 to 29, 1910. 
2. Rhipicephalus appendiculatus (Ref. No. 309). 
The larvae originated from mothers collected in Natal ; the eggs were 
laid on December 24th and the larvae hatched on January 30, 1910 ; they 
were placed on Calf 700 on February 27, 1910 {vide Experiment No. 1 (h) ). 
The engorged larvae were collected during the period when the parasites 
of East Coast Fever were frequently met with in the blood. These 
engorged larvae hatched on March 17, 1910, and the nymphae were placed 
on Calf 917 {vide Experiment No. 1 (c)), and transmitted the disease. 
x\nother lot was placed on rabbits, and the engorged nymphae were 
collected from June 3 to 7, 1910. They moulted on May 4, 1910. 
Testing the Ticks. 
1. Heifer 1059 was infested on August 29, 1910, with adult brown 
ticks (Ref. No. 342) of the first rabbit. A re-infestation was made on 
September 14th with ticks of the second rabbit (Ref. No. 309). On Sep- 
tember 19, 1910, 26 ticks were found attached. No reaction followed ; the 
heifer eventually died of East Coast Fever at " Burnside." 
2. Heifer 1019 was infested on June 23rd with 20 brown adults of the 
first rabbit (Ref. No. 342). On June 28th it was re-infested with 20 brown 
adults of the second rabbit (Ref. No. 309). On the following day 8 adults 
were found attached. On July 15th and 20th and on August 3rd and 
20th this heifer was re-infested with brown adults of the first rabbit 
