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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