270 QUEENSLAND AGRICULTURAL JOURNAL. {1 Ava., 1901. 
1. Cases of malaria have often heen observed in the absence of ticks. 
I have heard this theory maintained by many intelligent cattle-breeders, 
and at the outset of my researches it has often occurred to me to meet with 
infected animals without being able to discover ticks on them. 
We know to-day, in a most precise manner, that the disease may begin 
from the twelfth day - that is to say, ata time when the young ticks are 
scarcely 1 millimetre 5 in length by O mm. 8 in breadth. Now, if these ticks are 
not numerous, it is easy to understand how they may entirely escape notice, 
especially on a mere superficial examination. Long since then I have never 
found a case of natural malaria without ticks. 
I maintain, furthermore, the possibility of the appearance of the disease 
after the complete development and fall of the ticks. But in this case, which 
is, besides, very rare, because all the ticks do not evolute at the same time, I 
have always found traces of punctures, and especially several male living ticks 
still adhering to the skin. 
The long duration of the malarial inoculation explains how the disease may 
appear in the cold season. It is sufficient to experience a few fine days, or the 
unusual prolongation of the warm weather, for the ticks to hatch out late and 
slowly, and to infest the cattle, which will thus show symptoms of disease in 
the depth of winter at a time when there are, as a rule, no ticks. 
2. All animals corered with ticks do not contract bovine malaria. 
Nothing can be more true; but this observation does not prove the 
inocuousness of the tick. On the other hand, if it refers to animals bred in the 
midst of infested districts, either they have become immune in their youth, as 
we shall see later on, or else they have already had the malaria. 
Again, since the female tick is not virulent in herself, but only through 
the act of a micro-organism which she carries about by accident, it might be 
that she is sometimes exempt. 
Here arises a question of quantity and quality. How is it that some 
beasts, not refractory, remain for months in infested localities without being 
attacked ? 
This fact may be explained in two ways—either they are not immediately 
assailed by the ticks, or else, those which have effected a lodgment on the 
animal’s skin are only slightly or not at all infectious. But let them some day 
afford a lodgment to ticks rich in spores: they will forthwith contract the 
disease: A very plain fact inthe Argentine Republic is, that the geographical 
area of bovine malaria coincides strictly with that of the ticks. We shall see 
further on that it is not sufficient to transport ticks from one region to another 
to see them develop; it is further necessary that they should find these 
conditions favourable to their multiplication, otherwise they soon perish, and 
with them disappears all danger of the transmission of the disease. 
3. No one has yet been able to find the Piroplasma bigeminum in the body 
of ticks. 
This is due to the rapid transformation of the piriform hematozoa into round 
bodies, and then into spores extremely small and impossible to distinguish 
amongst all the mass of débrix contained in the ticks. Thanks to the latest 
knowledge acquired, I have been enabled to find hematozoa in the ticks, even 
in the pear-shaped form. 1 obtain this result with the greatest ease by the 
following method :— 
I place for three days on the skin of a receptive bullock, some ten ticks.* 
Sixteen days afterwards—z.e, five days before they arrive at maturity —I 
inject into the jugular of this bullock 10 ¢.c of very virulent blood. On the 
third, fourth, or fifth day following this inoculation, the animal, which will be 
very sick, will have an enormous number of hematozoa in the blood, so that 
the ticks in gorging themselves with it will infect themselves abundantly. 
_ *The number of ticks mus. be restricted, if one wishes to avoid the risk of imparting the 
disease earlier. 
