OF SOME EDIBLE AMERICAN FUNGI. 159 



the weight of nitrogen obtained by 6.25 and to express the 

 result as " crude proteids." * But even where the precaution 

 has been taken to remove non-proteid nitrogenous bodies by 

 extraction with alcohol, the application of the " proteid factor " 

 (6.25) to the N. of the residue may be quite misleading; for 

 our results have demonstrated that the amount of unavailable 

 nitrogenous material largely, if not entirely, non-proteid in 

 nature is frequently equivalent to over half of the non- 

 extractive nitrogen present (cf. Table II, p. 154). When it 

 is remembered that the various species of mushrooms exam- 

 ined contain from 75 to 90 per cent of water, the amount of 

 proteid in them appears strikingly small, even when calculated 

 on the total nitrogen hi the fungi, f For example, Morchella 

 esculenta, a species of average composition as regards total 

 solids (10.5 per cent) and nitrogenous constituents (0.48 per 

 cent N) could contain as a possible maximum only 3 per 

 cent of proteid, corresponding in this respect with potatoes, 

 peas, green corn, etc. ; $ the vegetarian would thus be obliged 

 to consume several kilos of the fresh morel to obtain the daily 

 requisite of 100 grams of proteid. The expression "vege- 

 table beefsteak " accordingly seems scarcely appropriate when 

 applied to mushrooms in a strictly chemical sense. Moreover, 

 the comparative poverty of many species in proteids is corrobo- 

 rated by the results of other investigations now in progress 

 in this laboratory, the yield of isolated substance being quite 

 small. The fungi thus form no exception to the ordinary 

 classes of fresh vegetable foods ; indeed, they take a decidedly 

 inferior rank in comparison with many. 



The carbohydrate content of the fungi is relatively high ; 

 but until more is known regarding the nature and digestibility 

 of the carbohydrate constituents of various vegetable foods, 

 it will be useless to draw comparisons. As dietetic accessories 

 the edible fungi may play an important part; but investiga- 

 tion has demonstrated that they cannot be ranked with the 

 essential foods. 



* Cf. Wiley, Agricultural Analysis, 1897, iii, p. 543. 



t Cf. Morner, C. Th., Zeitschr. fur physiol. Chemie, 1886, x, p. 615. 



} Cf. Atwater, W. O., Foods : Nutritive Value and Cost, loc. cit, p._27. 



