SPOLTA ZEYLANTCA. 



NOTE ON THE POSSIBLE TRANSMISSION OF SARCOCYSTIS 

 BY THE BLOW- FLY. 



By W. S. Perrin, B.A., Gonville and Caius College, Cambridge. 



TTT'HEN we were examining the gullets of some sheep infected 

 ^^ with Sarcocystis tenella, it occurred to Mr. Adam Sedgwick 

 and myself that the Blow-fly {Calliphora) or the Flesh-fly (Sar- 

 cofhaga) might afford a means of transmission of this parasite. 

 Accordingly experiments were instituted to test the hypothesis, 

 but owing, partly to pressure of other work and partly to the 

 difiiculty experienced in obtaining material richly infected with 

 Sarcocystis , the experiments, which had hitherto yielded only 

 negative results, were discontinued. At Dr. Willey's suggestion I 

 thought, however, that it might be useful to publish the following 

 account of our theory in Spolia Zeylanica, in the hope that some one 

 may be induced thereby to test it in Ceylon, where material 

 abundantly infected wdth Sarcocystis buhali is provided by the 

 carcases of buffaloes slaughtered for meat.* 



The experiments necessary to be performed are few and simple, 

 and a month's work might be sufficient to prove or disprove the 

 hypothesis ; while, if the result of the experiments were to show 

 that the hypothesis is correct, a discovery, not only of scientific, 

 but also of considerable economic importance, would be made, as 

 the presence of Sarcocystis in meat spoils it for human consumption. 



As is well known, Sarcocystis is a Protozoan parasite which 

 belongs to the Sporozoa, and is found in the muscles of various 

 vertebrate hosts. Nearly all slieept and pigs are infected, while 

 horses, oxen, buffaloes, mice, and rabbits frequently are. The 

 effect produced by the parasite upon the health of the host differs 

 for different animals. Sdrcocystis causes death in mice, the host 

 becoming rapidly overrun with the parasite, while in other forms, 

 e.g., buffaloes and sheep, the infection although widespread gives 

 rise apparently to no inconvenience. 



Sarcocystis forms elongated, whitish cysts in the muscles of the 

 host, which in the case of Sarcocystis huhali measure a half to one 

 inch in length and about a quarter of an inch in diameter. The 

 most frequent seats of infection are the oesophagus and the trunk 

 muscles in the region of the stomach, although any or all of the 

 muscles may be infected with the cysts. The cysts contain numer- 

 ous minute sickle- shaped spores which in Sarcocystis tenella are 



* See Spolia Zeylanica. vol. II., part VI., 1904, p. 65. 



f Bertram records that 182 of the 18.5 sheep he examined for S. tenella were 

 infected (Zool. Jahrb. Abth. f. Anat. V.). 



