152 



COMPOSITION AND NUTRITIVE VALUE 



digestion experiments were carried out with seven species of the 

 fungi. The procedure was modified after the Stutzer method. 

 About 2.5 grams dry substance were treated in a flask with 

 100 c.c. of an artificial gastric juice, containing 0.1 gram of very 

 active scale pepsin and having an acidity of 0.35 per cent 

 HC1. The flasks were frequently shaken, and after remaining 

 in a thermostat at 38 C. for twelve hours, the undissolved 

 residue was filtered off, washed free from acid, and again 

 treated in the flask for several hours at 38 C. with 100 c.c. 

 amylolytically active fresh chloroform-water extract of dog's 

 pancreas, a little chloroform being added to prevent putre- 

 faction or fermentation. Sodium carbonate (0.25 gram) was 

 then added, followed by 25 c.c. of a proteolytically active 

 thymolized extract of dry pancreas powder (Kuhne's method).* 

 At the end of seven hours the residue was again filtered on 

 a weighed filter, washed thoroughly with hot water, and dried 

 at 105 C. to constant weight. Undigested residue was thus 

 determined, and the nitrogen content ascertained by the 

 Kjeldahl method and expressed as nitrogen in residue. The 

 results expressed in percentages of dry substance are tabu- 

 lated below. 



Discussion of the Analytical Data. Nitrogen and Protein. 

 From the results obtained it is evident that the nitrogen (and 

 proteid) content of the mushrooms (or at least those species 

 examined) is considerably smaller than is ordinarily stated. 



* See Chittenden and Cummins, Studies from the Laboratory of Physio 

 logical Chemistry, Yale University, i, p. 109. 



