PIROPLASMA AND TRYPANOSOMA OF CATTLE. 153 



older calves of cows im^Dorted from Australia had been obtained, and on 

 these the first experiments were repeated and the previous results con- 

 firmed. 



Another difficulty in continuing the work was due to the fact that 

 during the dusty month of March it was hard to keep the blood 

 specimens sterile ; it was, therefore, often necessary in spite of the tropical 

 heat to carry on the experiments with the calves, in the laboratory with 

 the windows and doors closed. 



It was also difficiilt to keep the incubators at the desired constant 

 temperature because of the frequent changes in the atmospheric temper- 

 ature rendering necessary frequent regulation of the incubators. It is 

 desirable to mention these circumstances in order to give a correct 

 understanding of the difficulties encoimtered in carrying on the work. 



EXPERIMENTS WITH NEW-BORN CALVES FROM FRENCH INDO-CHINA. 



In the following experiments an attempt was made to determine : 



1. Whether the piroplasmosis of the "original calf" constituted a 

 species of Coast fever or one of Texas fever. 



2. Whether the trypanosomata, when isolated and injected into calves, 

 would cause in these animals a piroplasmosis or a tr3^panosomiasis, or 

 both. 



3. Whether after the injection of the fresh blood of the "original calf" 

 into other calves trypanosomata could be obtained from the animals by 

 culture. 



EXPERIMENTS. 



These experiments were carried on in the following manner : 



Calf No. 1 (infected icith cultures). — January 26, 1909; new-born female calf, 

 from Indo-China; ticks {Boophilus australis) present; nourished artificially. 

 Blood smears examined daily for piroplasmata and trypanosomata negative. 

 Blood culture negative. In order to exclude infection with surra, a monkey was 

 injected with 30 cubic centimeters of the blood subcutaneously ; it remained 

 healthy and free from parasites. (In all of the experiments, the native monkeys 

 were kept under observation for several months, and examinations of the blood 

 were made daily). 



On the 5th of February, 1909, calf No. 1 was injected with two five-day-old 

 cultures made from blood of the "original calf," and showing a good growth of 

 trypanosomata; at the same time a monkey was inoculated with a similar 

 culture subcutaneously. I had been unable to find piroplasmata in these cultures 

 on the day of the injection. Tlie monkey remained healthy and free from 

 parasites. On the 9th of February, 1909, the calf developed diarrhoea, but with- 

 out imdergoing much disturl)ancp of its general health. On the I'ith of February, 

 1909, the diarrhoea stopped. 



On the 12th of February a culture was attempted with the blood of the calf, 

 but gave negative results. On the 1.5th of February blood smears showed piro- 

 plasmata of the same morphology as those of the ''original calf" and some like 

 the riroftntna hifffmivvm. (See Plate IT. fig. 1, a, c, c, f, (/, h, and Plate V, figs. 



