1 Sepr., 1901.] QUEENSLAND AGRICULTURAL JOURNAL. _ 386i 
Jn Texas and in Australia numerous trials have been made of vaccination 
by the injection of the blood of diseased animals or of those lately recovered. 
I have also tried this process, and have proved it to be impracticable. On the 
one hand, it is not known whether parasites are injected capable of evolution, 
and as a consequence able to confer immunity ; on the other, one may super- 
induce the disease or even kill the animal. I have had 50 per cent. of deaths 
in this way due to preventive injections. 
I have sought to attenuate the virulence of the Piroplasma bigeminum, but 
the results obtained are, up to the present, not perfect. At the same time I 
am convinced that one may succeed in obtaining a virus which will transmit the 
mild form of bovine malaria by inoculation without danger. For my part, 
I am actively engaged in this work. Thanks to M. Uriburu, a very pro- 
gressive Argentine breeder, I was enabled lately to make an experiment on tour 
bulls, which he had obligingly placed at my disposal. From the results 
obtained I hope to derive some valuable indications of the solution of the 
problem. I only cite the anthrax vaccine, so much extolled as a protection 
against the bovine malaria, to state that it is absolutely inefficacious. In all 
my experiments, the animals vaccinated as a protection against anthrax con- 
tracted the disease as well as the controls. 
CONCLUSIONS. 
My intention in this work has been to repeat the study of bovine malaria. 
Amongst other points in the conclusions of Smith and Kilborne, I con- 
firm— 
1. The specificness of the Piroplasma bigeminum. 
2. The alteration of the red corpuscles as the principal cause of the 
symptoms and lesions observed. 
3. The inoculability of the disease to cattle by sub-cutaneous or intra-venous 
injections of the blood, viscera and tissues of the blood corpuscles. 
4, The transmission of the disease by ticks. 
5. The danger of sending cattle from immune districts to infected districts. 
6. The virulence of the blood of healthy animals bred in infected centres 
and that of the ticks which they harbour. 
7. The sensitiveness of adult cattle and the almost indifference of very 
young cattle to the Pzroplasma. 
8. The non-inoculability of bovine malaria in the case of rabbits, guinea- 
pigs, sheep, and pigeons. 
9. With Nicolle and Adil-Bey. The permanence of the Péiroplasma.in 
the tissues of cattle infected for a long time. 
I would observe further : 
A. That the consecutive immunity by a first attack is more lasting than 
Smith and Kilborne have believed. 
B. That the examination of the blood, although it is the most important 
item of the diagnosis ante-mortem, is occasionally at fault. 
C. That there exists, in fact, an atypic form of the disease, in which the 
corpuscular loss is little accentuated, or very slow, and in which the corpuscles 
of the general circulation are not invaded by the Piroplasma, or are only so 
invaded at the approach of death. , 
D. That this form does not correspond to the mild disease; in the latter, 
indeed, the corpuscular infection and the destruction of the blood corpuscles 
begin from the commencement of the disease, but are of no great importance. 
E. That the mild form is not caused by the punctiform hematozoa, as 
Smith and Kilborne thought, but by the Piroplasma type. 
Lastly I add: 
(a.) The history of the evolution of Piroplasma bigeminum, incomplete 
until now, the discovery of the spore, the exact form of the parasite. 
(%.) The culture in a warm chamber of Piroplasma bigeminum in the 
round form. 
