PIROPLASMA AND TRYPANOSOMA OP CATTLE. 163 



more strikingly b}^ the fact tliat as a rule only a third of the ten to twenty 

 cultures from the calves showed trypanosomata; in fact, not infrequently 

 trypanosomata were found in only a single tube. Hence they must have 

 been present in extremely small numbers in the blood of the infected 

 calves. This fact is in full accord with my experiences with a strain of 

 Trypanosoma hrucei of low virulence with which 1(10) worked for years 

 under the direction of Eobert Koch. I succeeded in infecting other 

 animals with the strain, but in tlie blood of the original animal itself, 

 a mare from Togo, I did not find trypanosomata in spite of observations 

 lasting for months. I am inclined to believe that the trypanosoma 

 described in the present experiments would appear in greater number in 

 the fresh blood of a species of animal which is especially susceptible to it 

 could one be found. Dogs which were given very large doses of the 

 blood of the Togo mare, subcutaneously or intraperitoneally, after a 

 certain period of incubation, showed the tsetse trypanosomata in their 

 blood. The failure to find trypanosomata in the fresh blood of the 

 "original calf" and in the blood of the calves inoculated with cultures of 

 this trypanosoma can hence be explained by the extreme scarcity of the 

 trypanosomata. However, it is possible that the parasites are present in 

 an especial form, but not that of the piroplasmata described. 



CONCLUSIONS. 



The experiments justify the following conclusions: 



1. In the Philippine Islands there are domestic cattle apparently 

 quite healthy which are carriers of the parasite of surra. These cattle 

 are a continual danger, especially for horses in which surra always runs a 

 fatal course, as has been shown by the works of Smith and Kinyoun(ll), 

 Curry(12), Salomon and Stiles(13), Strong(14), Musgrave, William- 

 son and Clegg(15, IG). 



2. In the Philippine Islands there exists a variety of Texas fever 

 which is perhaps identical with that seen by Jobling and Woolley(17) in 

 the 3'ears 1903 and 1904. However, this can not be stated with certainty 

 to-day, because these investigators gave no accurate description of their 

 parasites. The piroplasma is probably of Indo-Chinese origin. It is a 

 variety of Piroplasuui. higcuumim and shows in certain culture media 

 developmental forms which correspond to those described by Robert 

 Koch in the tick for Piroplasma, higeminum. Forms similar to those 

 seen in the early stages of the development of Piroplasma higeminum by 

 Koch and to those of the Manila ])iroplasma have been found in artificial 

 media by Kleine(l(S) for Piroplasma canis, and by Marzino\vsky(19) 

 for Piroplasma cqui. Besides the early forms of Kocli, the Manila 

 parasite shows other forms with a different moi-phology. 



3. This piroplasma, when kept in tlie boiiillon employed and at a 

 temperature of 29° to 31° C, dies within five to ten days. 



86321 2 



