154 COMPOSITION AND NUTRITIVE VALUE 



n. 



In considering the relatively high nitrogen content of the 

 residue resisting digestion, it is to be noted that this is not 

 necessarily derived from unattacked proteids. Winterstein * 

 and others have shown that the " cellulose " preparations 

 obtained by the usual methods from various fungi contain a 

 considerable percentage of nitrogen ; thus a preparation from 

 Boletus edulis contained 5.5 per cent N, and this substance, 

 like similar preparations from Agaricus campestris, Morchella 

 esculenta, and other forms, yields glycosamin, C 6 H n O 8 . NH,, 

 on decomposition with HC1. It is thus allied to the chitin 

 found in the animal kingdom; further investigation in this 

 direction is highly desirable. 



It is of interest in this connection to compare the results 

 obtained by C. Th. Mb'rner f in an investigation of thirteen 

 species of fungi common in Sweden. Nitrogenous constitu- 

 ents alone were considered, total N and extractive N, as well 

 as digestible and indigestible N being determined by methods 

 analogous to those used in the present research. Morner's 

 results, summarized in the following table, show a close agree- 

 ment, in general, with those already given for different 

 American species. 



Winterstein, loc. cit. ; also, Berichte der deutschen chemischen Gesell- 

 schaft, 1894, xxvii, p. 3113 ; xxviii, p. 167. 



t Morner, C. Th., Zeitschr. fur physiol. Chemie, 1886, x, p. 608. 



