462 HEPBURN AND JONES— BIOCHEMICAL STUDIES 



the former and 0.2 percent of the latter reagent in the final solution; 

 then 0.2 gram of carmine fibrin was added. A control experiment was 

 made exactly like the experiment proper, except that 12 cc. of distilled 

 water were substituted for the press juice. The incubation was made 

 at room temperature. In the control experiment, the carmine fibrin 

 showed signs of incipient digestion in 45 minutes, and had completely- 

 dissolved in 14 hours. In the experiment proper, the carmine fibrin 

 was only partly dissolved at the end of 17 hours, but was completely 

 dissolved at the end of 22 hours. 



Since the press juice markedly retarded the digestion of carmine 

 fibrin by both pepsin and trypsin, both antipepsin and antitrypsin were 

 present in the larvae of Sarcophaga sarraceniae. 



T her mo-stability of the anti proteases. The experiments proper were 

 also carried out as described above, except that the 12 cc. portion? of 

 press juice were boiled and cooled to room temperature, then used 

 without filtration. The protein in the press juice was coagulated by 

 the heat on boiling. The digestion of carmine fibrin by both pepsin and 

 trypsin was retarded to about the same extent as when unboiled press- 

 juice was used. The coagulated protein of the press juice was dissolved 

 completely by pepsin and by trypsin (pancreatin) only after digestion 

 at room temperature for 7 to 8 days, the coagulum remaining long after 

 the carmine fibrin had disappeared. These results indicate that the 

 antiproteases — antipepsin and antitrypsin — of the larvae were ther- 

 mostabile. They also indicate that the coagulated protein of the press- 

 juice either adsorbed antiprotease and thereby resisted digestion, or 

 else was in itself not readily digestible. 



The methods used in the preceding experiments were based on those 

 described by Fischer (1) and by Wohlgemuth (3) The trikresol served 

 as a bactericide. 



In this study, antiproteases have been found in the larvae of the 

 Sarcophaga associates of the pitcher plant, Sarracenia flava. The larvae 

 of other species of Sarcophaga, and of several other dipterous genera, 

 are likewise able to live and escape digestion in an environment rich in 

 proteolytic enzymes; probably these larvae also contain antiproteases 

 which protect them from digestion. Thus Sarcophaga haemorrhoidalis 

 Fall, can live in the human intestinal tract; Haseman (4) has recently 

 pubUshed a detailed account of a series of cases of intestinal myiasis 

 in man, due to the presence of the larvae of this species in the intestines; 

 Aldrich (5) gives an additional and similar case in which the parasite 



