158 



COMPOSITION AND NUTRITIVE VALUE 



into dextrose by hydrolysis with acids,* the results of analysis 

 must be somewhat low. Nevertheless the data may be of 

 comparative interest as indicating a high content of soluble 

 carbohydrate. 



DEXTROSE FROM HYDROLYSIS OF WATER-SOLUBLE 

 CARBOHYDRATES. 



To what extent these soluble carbohydrates are available for 

 absorption in their natural form or after digestion it is im- 

 possible at present to say. Such qualitative tests as were 

 made showed them to be transformed to reducing sugars 

 rather slowly by the action of saliva. The large undigested 

 residues (26-59 per cent) found hi artificial digestions like- 

 wise suggest that they are not completely transformed in the 

 alimentary canal. Reference may here be made to the obser- 

 vations of Stone f in feeding experiments on animals. He 

 found that the pentosans, which are so widely distributed in 

 vegetable foods, are to a marked degree less digestible than 

 the carbohydrates, with which they have usually been indis- 

 criminately classed in analyses. 



After the presentation of the preceding analytical data it 

 will scarcely be necessary to draw any elaborate comparison 

 between the fungi and other well-known vegetable substances 

 considered as food-stuffs. It may be well to emphasize the 

 deficiencies of the methods commonly followed in estimating 

 the proteid content of vegetable foods, and to call attention 

 to the erroneous inferences which are consequently drawn 

 regarding the nutrient value of these products. Thus it is 

 not unusual in the construction of dietetic tables to multiply 



Winterstein, 1894, loc. cit., xix, p. 77. 



t Stqpe, American Chemical Journal, 1894, xiv, p. 13. 



