146 COMPOSITION AND NUTRITIVE VALUE 



diet, the writer has gladly followed the suggestion of Professor 

 Chittenden to ascertain something more definite regarding the 

 composition of edible mushrooms, with particular reference to 

 their nutritive qualities. 



Methods. Specimens were obtained from various sources, 

 and in some instances different samples of the same species 

 were examined.* The common methods of studying the com- 

 position of agricultural products have been adopted, the direc- 

 tions given by the Association of Official Agricultural Chemists 

 being closely followed in most instances.! The mushrooms 

 were cut up finely and thoroughly mixed. Samples were 

 taken for the determination of moisture, while the bulk of the 

 material was dried on a water-bath and then ground up to a 

 fine powder. Dried to constant weight at 105 C., this 

 served as material for analysis. 



Ash was determined in the usual way, the incineration being 

 carried on with the lowest possible heat. The mushrooms 

 employed were previously cleaned with considerable care, and 

 thus an excess of inorganic impurity, such as sand, was 

 avoided. 



Ether extract was obtained by treating the material with 

 anhydrous and alcohol-free ether in a Soxhlet extractor for six- 

 teen hours, the extract being finally dried in vacuo to constant 

 weight. Recently BugdanowJ has shown that this method is 

 insufficient to remove the last traces of fats completely from 

 some vegetable materials, even when they are finely divided. 

 The error is not sufficiently large, however, to affect the 

 general conclusions from the analyses. In order to examine 

 the extract for cholesterin it was saponified in the usual way 

 with alcoholic potash. Cholesterin (or closely allied sub- 

 stances) was detected by Salkowski's reaction ; but the method 

 of separation employed obviously does not exclude the possi- 



* Acknowledgment is gratefully made of specimens obtained through the 

 courtesy of Mr. Hollis Webster, of Cambridge, and Captain Mcllvaine, of 

 Philadelphia. The material used has in every case been identified, or ver- 

 ified, by Dr. A. W. Evans, to whom our thanks are due. 



t See Wiley, H. W. : Agricultural Analysis, 1897. 



J Bugdanow : Archiv . d. ges. Phyeiol., 1897, Ixviii, p. 408. 



