264 QUEENSLAND AGRICULTURAL JOURNAL. {1 Ave., 1901. 
coming from districts where bovine malaria was prevalent. Then they placed 
healthy cattle in these paddocks, and saw them contract the disease. 
I did not wish to make further experiments such as this, because there are 
no ticks in the province of Buenos Ayres, where my laboratory is situated, and 
I did not wish to create one or more centres of infection. Nevertheless, I made 
one experiment; but it was carried on under special conditions, and was 
intended rather to prove that ticks are not always dangerous, even when they 
come from localities where bovine malaria is prevalent. I will describe this 
experiment further on, because it is of special importance. 
The propagation of bovine malaria by means of ticks is much more easy to 
demonstrate when young larve recently hatched in the laboratory are employed. | 
Although this method of propagating the disease has been clearly demonstrated 
by Smith and Kilborne, and again, later on, in Australia, by Pound, no 
faith was placed in the results until lately, in 1898, when R. Koch made the 
same observations in South Africa. 
I have therefore, in my turn, tried to. verify the experiments of Smith and 
Kilborne as far as regards the bovine malaria of the Argentine Republic. 
I have made some twenty experiments of this nature, of which eleven were 
plainly positive. The others did not furnish any visible result. I undertook the 
work under various conditions, making use of ticks from different localities, 
taken either from healthy or from affected beasts. In all cases, the eggs were laid 
and hatched out in small clean glass receptacles containing not the slightest 
particle of earth nor the least débris of any kind. The laboratory in wie I 
conducted all my experiments is about 350 kilometres (218 miles) from any 
centre of bovine malaria, in a zone absolutely immune. (Plate XVI.) Lastly, 
the animals I experimented on came from the south of the province of Buenos 
Ayres. They were placed in stalls, and it was impossible for them to be 
accidentally contaminated. 1 will describe two experiments, one with ticks 
taken from an affected beast, the other with ticks from a healthy animal. 
1._MILD DISEASE PRODUCED BY TICKS TAKEN FROM A BEAST WHICH 
HAD DIED OF MALARIA. 
Bullock, aged 2 years. Cross-bred Durham. ' 
On the 5th June, 1899, I placed on the skin of this bullock about 300 young 
ticks hatched two days before, taken from mothers gorged with blood, collected in the 
province of Cordoba, from an animal which had died of bovine malaria on 2nd May, 
1899. : 
June 6.—Temperature, 38°7 C. Number of red corpuscles, 8,300,000 per m.m.c. 
Fy 7 Fr} 38°3 C. As on the previous day, the general condition is 
good; nothing in the corpuscles. - 
a8 38°7 C. 
Ae = 38°6 C. 
5 y ¥ 38°6 C. 
4 il s 38°6 C. 
marl? es 38°9 C. 
1B pape SRoR TC! 
Soa! i‘ 38°4 C. 
et: 4 38°5 C. 
i 108 . 38°7 OC. 
FN S17, i 38° C. 
Aenls be 38°2 C. 
5 * 39°1 C. 
5 eu f: 39°6 C. 
yal is 39° ©. 
29 39° C. 
Every day I counted the red corpuscles. Their number varied a little above and 
below 8,000,000. None have yet contained any micro-organism. ‘The animal is in good 
health. 
June 23.—TLe., twelve days after the commencement.of the experiment, the 
temperature rose to 39°9 C., and by a most careful and minute examination I found a 
very few types of Piroplasma bigeminum. The animal does not appear to be very 
sick. The corpuscles number 7,800,000. 
oe A 
