

Transmission and Inoculability of Spirillum Theileri. 505. 
decoloratus. To prove this inference the following experiments were carried 
out :— ie | 
Six heifers, about the same age, which came from Aliwal North, were 
stabled on the premises of the laboratory, and successfully infected with 
— Spirillum Theileri by a tick. In these experiments the tick (Rhwpicephalus 
decoloratus) was fed on the sick cattle during and shortly after the febrile 
reaction, when the Spirillum was noticed in the blood. Spirilla were found 
to be present in the blood of the healthy animals in some experiments in 
13 days, in others in 17 days, after the infected ticks had fed on them. The 
above experiments thus prove that the Spiriulum Thewleri is conveyed from 
the sick to the healthy animals by this tick. 
The Effect of Injection of Blood from Cattle Suffering from Sprrillosis into 
Cattle, Sheep, Goats, and Horses——Oxen and sheep were inoculated with blood 
containing Spirilla from animals suffering from the disease. Spirilla appeared 
in their blood after two or three days. It is possible that goats can also be 
infected by the Spirillum, since a slight febrile reaction after inoculation was 
observed in two cases, but the Spirillum has not yet been demonstrated in 
the blood of goats. One horse was injected, but proved refractory to 
spirillosis. The incubation period of the disease, produced by inoculation of 
infected blood, is as short as two and three days, whilst after tick infection 
the duration is 13 to 17 days as above noted. 
The development of the blue tick from the larva to the adult takes place 
onthesame host. It is necessary, therefore, that the infection of this spirillosis 
should pass through the egg stage of the tick. When the egg hatches 
into a larva, the larva is capable of giving the disease to a healthy animal. 
As the tick remains on the same host for two or three weeks, it is evident 
that as an adult it may reinfect itself with Spirillar blood, taken from the 
same animal it infected asa larva. This is possible on account of the short 
incubation period of the disease. None of the animals died from spirillosis. 
Enumeration of the red blood corpuscles shows that the Spirillum produces 
slight anemia, not sufficient, however, to cause death. Some of the animals 
went off their feed, and a loss of condition was noticeable. 
The Blood of an Ox which has Recovered from Spirillosis 1s Infectwe and 
Blue Ticks fed on such an Animal can acquire the Infection and Transmit it to 
Healthy Animals—Five sheep were injected intravenously with defibrinated 
blood of an immune ox and contracted spirillosis. By an immune ox I mean 
an animal which has recovered from an attack of spirillosis and is no longer 
susceptible to the disease. Thus the blood of the healthy immune ox is 
infective, although it is impossible to determine the presence of the parasite 
microscopically. 
