6i8 Veterinary Medicine. 



these rings can be found at will by inoculating a calf with 

 the blood of a recovered Texas fever animal and examining the 

 blood daily. Moreover Cape Colony cattle having such ring; 

 shaped bodies in their blood die promptly when exposed to the 

 Coast /ever. Robertson, Bowhill and Dixon agree with Theiler, 

 The parasite is best stained in eosin and azure II, having been: 

 fixed in alcohol and ether and then immersed in the staining 

 mixture (freshly mixed) and left in an incubator at 30° F. for 

 two hours. 



Tick bearers. In the infected areas Theiler found the blue tick 

 (Rhipicephalus decoloratus) the most abundant. I^ounsbury, in 

 a series of experiments, was especially successful with the mature 

 brown tick (R. Appendiculatus), the larva of which had fed on 

 Coast fever cattle. A single tick produced the disease. But the 

 larval brown ticks hatched from eggs laid by mature females 

 taken from Coast fever cattle proved noninfecting. I,arval blue 

 ticks also failed. The brown tick nymphse on the other hand 

 which as larvae had fed on- Coast fever cattle proved infecting. 

 He notes further that the blue tick clings to the same host from 

 the larva just hatched to maturity, whereas the brown tick drops, 

 off before each moulting and thus the same tick may infect at 

 least two cattle in succession. In a series of careful experiments, 

 the blue tick failed to convey the disease (lyounsbury, Robertson). 



Nature of disease. This is in the main the same as in its near 

 ally, Texas fever, with which it is often confounded and even 

 complicated. I<ike that it is not communicated directly, except 

 by the (repeated) transfer of blood, and when conveyed by ticks, 

 in pastures, roads and buildings there is the delay of a fortnight 

 for moulting, between the introduction of the sick ox and the 

 infection of the susceptible animal. A week more is required 

 for incubation. Koch says the sick ox may be stabled with the 

 susceptible without transmitting the disease but this can only be 

 true when the former has been divested of its ticks. The disease- 

 differs from Texas fever in this that there is no such destructioa 

 of red globules, nor staining of the urine by freed haemoglobin. 

 An attack of Rinderpest ox of Coast fever in an ox recovered from 

 Texas fever (salted) determines a relapse of the latter (Robert- 

 son). 



Symptoms. After an incubation of six to twelve days, there 



