LINXEA^' SOC'IEXY OF LONDOX. 45 



Fellows: — Mr. Philip AValter Mackinnon, Mr. Thomas George 

 Hill, and Mr. Eric Drahble. 



jMr. Alfred William Alcock was proposed as a Fellow. 



The following papers were read : — 



1. " On Obesiella, a new Genus of Copepoda." Bv Dr. W. G. 

 Eidewood, F.L.S. 



2. " On Modern Methods in Mycology." By Georf^e Massee, 

 F.L.S. 



3. "Further Obseryations on the Owls, especially their Skeleton." 

 By AV. P. Pyeratt, A.L.S. 



ABSTRACTS. 



jS'ovember "ilst, 1901. 



The President gaye some account of his iuyestigation of the 

 proteolytic enzyme of Xepenthes. He began by pointing out that 

 in the higher animals there are two distinct proteolytic enzymes : 

 (1) pepsin, secreted by the stomach ; (2) trypsin, secreted by the 

 pancreas. The action of pepsin npon the more complex proteids 

 (albumin, fibrin, &c.) is to conyertthem by hydrolysis into simpler 

 proteids known as peptones ; whereas the action of trypsin is not 

 only to conyert these proteids into peptones, but, further, to 

 decompose the peptones into non-proteid nitrogenous substances, 

 such as leucin, tyrosin, &c. Among these final products of tryptic 

 digestion there is a substance called tryptophane, \\hich has the 

 property of giving a pink or yiolet colour on the addition of chlorine- 

 water. Hence this colour-reaction may be used as a means of 

 determining the nature of the digestion to which any proteid may 

 haye been submitted. 



xls the result of previous researches upon the nature of the 

 digestion effected by the enzyme of Nepenthes, the President had 

 come to the conclusion that it was not peptic, as had been supposed, 

 but essentially tryptic. This conclusion has recently been called 

 in question by Clautriau (Acad. Eoy. de Belgique, 1900), who 

 re-asserts the peptic character of the enzyme. By means of the 

 tryptophane-reaction, which is readily given by the products of a 

 Nepenthes digestion, the President has been able to establish the 

 correctness of the view that the enzyme is tryptic. 



The tryptophane-reaction has also been found to be given by a 

 number of extracts of plants which are known to contain a 

 proteolytic enzyme ; for instance, pineapple-juice, papain, figs, 

 germinating bean-seeds, &c. It seems probable, therefore, that 

 proteolytic digestion in plants is always tryptic — that there is, in 



