The Life of the Fly 



no matter which, are not turned Into liquid; 

 they become a pea-soup of a clarety brown. 

 The liver, the lung, the spleen are attacked to 

 better purpose, without, however, getting be- 

 yond the state of a semi-fluid jam, which easily 

 mixes with water and even appears to dissolve 

 in It. The brains do not liquefy either: they 

 simply melt into a thin gruel. 



On the other hand, fatty substances, such as 

 beef-suet, lard and butter, do not undergo any 

 appreciable change. Moreover, the worms 

 soon dwindle away, incapable of growing. 

 This sort of food does not suit them. Why ? 

 Apparently because It cannot be liquefied by 

 the reagent disgorged by the worms. In the 

 same way, ordinary pepsin does not attack 

 fatty substances; it takes pancreatin to reduce 

 them to an emulsion. This curious analogy 

 of properties, positive for albuminous, nega- 

 tive for fatty matter, proclaims the similarity 

 and perhaps the Identity of the dissolvent dis- 

 charged by the grubs and the pepsin of the 

 higher animals. 



Here is another proof: the usual pepsin 

 does not dissolve the epidermis, which Is a 

 material of a horny nature. That of the mag- 

 gots does not dissolve it either. I can easily 

 rear Bluebottle-grubs on dead Crickets whose 

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