60 SPOLIA ZEYLANICA. 



sealed with wax. When the larva is large and the gut contents 

 considerable, the fluid is divided between two or more coverslips 

 according to the size of the gut. Stained preparations can readily 

 be made by gently spreading the fluid over the surface of the cover- 

 slip and allowing the film so obtained to dry. The dried film is 

 then immersed in absolute alcohol for ten minutes, again dried, 

 and finally stained for fifteen minutes in an aqueous solution of 

 Giemsa's ready prepared solution of cosine and azure II., one drop 

 of the stain to one cubic centimetre of distilled water. After 

 staining, the film is washed in water, allowed to dry, and finally 

 mounted in cedar wood oil. This method is very barbarous, but 

 it has the advantage of not consuming much time. It proved very 

 convenient for diagnosing the presence of S. tenella in the gullets 

 of sheep, which did not present well-grouTi cysts. For accurate 

 investigation of structure some wet method of fixation must of 

 course be adopted. 



In the one set of experiments which I performed with gullets 

 of sheep infected with Sarcocystis tenella negative results were 

 obtained with the larvse, but as the gullets used had no cysts 

 upon them , the parasite only having been detected by microscopic 

 examination of teased fragments of the gullet, the results cannot 

 be regarded as by any means conclusive. Assuming either that 

 the spores of Sarcocystis or developmental forms of these are shown 

 to be present, the next step would be to allow some of the larvse 

 to develop into adult flies and to examine the organs of the adult 

 for further stages. It seems unlikely that these later stages would 

 be found in the gut of the full-grown blow-fly, as the histolysis which 

 takes place at the metamorphosis is so complete that the larval 

 organs entirely disappear, the adult organs being reconstituted 

 entirely from the imaginal discs.* 



Finally, experiments upon transmission to uninfected buffaloes 

 would be made. 



There is a parasite present in the gut of the blow-fly with which 

 any one working with blow-flies is likely to meet, and of which a 

 short description may be useful. This is a biflagellated organism 

 allied to the Trypanosomes and belonging to the genus Herpetomonas. 

 Two allied species, H. muscce domesticce and H. sarcophagce, both 

 of which give rise to cysts, have been fuUy investigated by Prowazek.f 

 It seems very improbable that this form has anythmg to do with the 

 life-cycle of Sarcocystis, but in view of the protean transformations 



* Vide " The Blow-fly," Lowne, vol. I., p 4. — " If the pupa-case be opened 

 just before it becomes black, it will be foTind to contain nothing apparently 

 but a white cream-like fluid ; but on careful microscopic examination some 

 of the imaginal discs will be detected and many of the miascles of the larva 

 still remain at the posterior end." 



+ Die Entwicklung von Herpetomonas. Arb. a. d. kais. Gesundheitsamt. 

 Bd. XX., Heft 3, 1904. 



