BIBLIOGRAPHY. 
517 
Prof. Lignieres has succeeded in transmitting experimentally 
malaria to 127 bovines by intravenous or subcutaneous vaccina¬ 
tion of infected blood. All animals other than bovines are re¬ 
fractory. 
Smith and Kilborne have proved the part played by the 
tick ( Syodes bovis of Riley, Boophylus bovis of Curtice, Rhypi- 
cephalus annutatus of Say), in the spreading of Texas fever. In 
Argentina, says Lignieres, the presence of malaria coincidates 
exactly with that of the tick. The author has found the piro- 
plasma bigeminum in the bodies of ticks. Yet, a great number 
of infected ticks, crushed together, have been inoculated under 
the skin of cattle without producing the disease, while a few of 
these parasites placed on another steer gave him malaria. In¬ 
deed, the rhypicephalus contains the virus in the state of passive 
spores, which by themselves are powerless to produce the dis¬ 
ease ; in natural contagion, it is the venomous saliva of the 
tick, deposited in the prick with the passive spore, which insures 
its growth and afterwards the disease. 
No treatment can succeed with that disease ; prophylaxy 
alone can. First of all, attention must be given to the ticks, 
essential agents of the transmission of the disease ; animals must 
not travel through regions infested by ticks. Animals born in 
infected regions offer a great resistance to the disease on account 
of the immunity gained by benignant attacks during the first 
months of their life. The parasite never does entirely disappear 
from the organism of animals that have resisted the disease and 
their presence is not in contradiction to the idea of immunity. 
Lignieres shows that in malaria, the refractory condition is 
the consequence of successive immunities, which explains its 
persistency. 
Taking into consideration the resistance of young animals, 
it was thought to expose them to the infection of ticks with the 
idea of giving them a benignant form of the disease, and thus 
give them certain immunity to resist another fatal attack. But 
this method has the objection of often giving a deadly disease 
to young animals and of creating new centres of tristeza. 
Prof. Lignieres has then looked for a more practical mode of 
vaccination. He says : “ I have tried to attenuate the viru- 
lency of the piroplasnia ; the lesults that I have obtained so 
far are not yet perfect, but I am convinced that a vaccine shall 
be found whose inoculation will transmit the benignant form 
of the disease.” 
Since the publication of this excellent book, Prof. Lignieres 
