PIROPLASMA AND TRYPANOSOMA OF CATTLE. 161 



on April 28 and May 5. Piroplasmata were still absent on May 17, 

 the thirty-second day after infection with the cultures. 



The calf was killed on May 17. The autopsy showed hsemorrhagic lymph glands 

 which were somewhat enlarged. Otherwise no pathological changes were noted. 

 The plasma bodies of Koch were not found in smears from the spleen or from 

 the lymph glands. 



The experiments on calves Nos. 8 and 9 show that it is possible to 

 separate the trypanosoina and the piroplasma, the parasites infecting the 

 "original calf." The importance of this result is the same, whether it 

 was accomplished by the fact that both of the calves were immune to the 

 piroplasma or, as I believe, by the killing of the piroplasma through 

 keeping the culture for a long time at a temperature of 29° to 31° C, 

 wliereby the capability of the trypanosoma to cause infection was not 

 destroyed. 



FURTHER HISTORY OF THE "ORIGHSTAL CALF." 



The "original calf" remained in good health and its blood contained 

 continuously the piroplasma described above ; the trypanosoma was culti- 

 vated rejjeatedly from its ))lood, for the last time on April 7. At this 

 time piroplasmata were also still present, biit trypanosomata could not be 

 found by microscopical examination even in centrifugated blood. On 

 May 19 while still in the best of health the calf was killed. The 

 autopsy showed numerous hfemorrhagic lymph glands which were 

 swollen to the size of a pea or bean; this was particularly noted in 

 the mesenteric glands. The spleen was enlarged and somewhat soft. 

 Otherwise no pathological changes were observed. The plasma bodies of 

 Koch were not found in smears either from the spleen or from the lymph 

 glands. An infection with Coast fever could, therefore, be excluded. 

 A mild infection with Texas fever, or a variety of this disease had 

 undoubtedly existed. 



RESULTS OF ALL THE EXPERIMENTS. 



From all the experiments we may conclude: 



1. The "original calf" was infected with a piroplasma belonging to 

 the Texas fever group. 



2. It was also infected with a trypanosoma hitherto unknown. 



3. No evidence was obtained of a transition in the blood cultures 

 of the piroplasmata into trypanosomata or, on the other hand, of a 

 transition of the trypanosomata, in the blood of the aninuil infected witli 

 them, into piroplasmata. 



4. The infection witli piroplasmata of calves Nos. 2, 4, G, and 7 

 rendered calves Nos. 6 and 7 slightly sick, wliile calves Nos. 2 and 4 died 

 of another disease, before sufficient lime had elapsed for tlie symptoms 

 of piroplasmosis to develop. 



5. Calves which have been inoculated with tlie trypanosoma apparently 



