riRUPLASMA AND TRYPANOSOMA OF CATTIJi). 159 



of the piroplasmata into tlie developmental forms of Koch as seen 

 in the cultures from the blood of calf No. 4 was not observed. On 

 account of the scarcity of the parasites these forms were not specially 

 searched for, since, according to the experience with calf No. 4, a multipli- 

 cation of the piroplasmata in these cultures w^as not to be expected. 



The calf became thin, but suffered in general only slightly from the 

 infection as is the custom with calves inoculated with virulent blood 

 from Texas fever cases. 



It was killed on May 13 and no pathological lesions were found in the 

 internal organs; no plasma bodies of Koch were seen in smears from the 

 spleen and lymph glands. 



Calf No. 7 (repetition of the experiments on calves Nos. 2, 4, '^f'-d 6). — March 

 26; female Australian calf about 4 months old; free from ticks; blood culture 

 negative; smears from the surface of the centrifugated defibrinated blood, free 

 from parasites. Thirty cubic centimeters of the blood of the calf were injected 

 subcutaneously into a monkey, which remained healthy and free from parasites. 



March 26 : The calf received subcutaneously 50 cubic centimeters of blood from 

 the "original calf." 



April 1 : Piroplasmata found present in blood smears. They remained numer- 

 ous until the 5th of April, and from that time were present only in small 

 niunbers. 



On April 1, 2, 3, 14, and 30 blood cultures were made which were 

 negative in regard to trypanosomata, hut positive with regard to the 

 developmental forms of the piroplasmuta described by Koch. (See Plate 

 VI, figs. 28 and 29.) 



April 3 : Animal passed a very hard stool with streaks, of blood. 



April 30 : Examination of the blood showed that almost all the piroplasmata 

 revealed the morphological characteristics of those obsei'ved in the "original 

 calf"; the Piroplasma higeniintim form was rare. 



The calf suffered but little from the infection. Only a moderate anaemia was 

 present. 



It was killed on May 12. Tlie autopsy showed a slight icterus of the liver, 

 which was the only pathological change observed. No plasma bodies of Koch 

 were found in smears from the spleen or lymph glands. 



The results of the experiments on calves Kos. 6 and 7 confirm those 

 obtained with calves Nos. 2 and 4. 

 They show — 



1. The presence of an infection belonging to the Texas fever group. 



2. The failure to transfer trypanosomata by means of an injection 

 of the fresh blood of the "original calf." 



After experiments on calves Nos. 2, 4, 6, and 7 had resulted as 

 described above it only remained to confirm the results of tlie experiments 

 on calves Nos. 1, 3, and 5. Tlie experiment on calf No. 3 liad indicated 

 that by using a trypanosoma to culture seven days old the pirosonuita 

 contained therein could be excluded so far as the production of an infec- 

 tion with them was concerned. Therefore, it was possible that the 



