98 ALIMENTATION. 



sisted upon ; but as far as quantity and variety of essential 

 alimentary principles are concerned, there is no one of them 

 which is comparable to wheaten bread. 



The ordinary potato is by far the most important of the 

 leguminous roots. It undoubtedly forms a larger part of our 

 vegetable food than any other article except wheat ; and of all 

 vegetables it is the one that becomes least distasteful from 

 continued use. In Ireland, the potato forms the greatest part 

 of the diet of the poorer classes, but those who live almost 

 exclusively upon it are not well nourished. It is generally 

 taken after the starch-granules have been disintegrated and 

 its general structure softened by cooking ; but in a raw state 

 it has been found very useful in scurvy, or where there is a 

 scorbutic tendency, particularly in armies. A study of the 

 proximate composition of the potato shows that it cannot of 

 itself be capable of maintaining the organism in full vigor, 

 on account of its great deficiency in nitrogenized and fatty 

 materials : 



Pfoximate Composition of the Potato? 



Water , 66'875 



Starch and amylaceous fibre 30-469 



Albumen O503 



Gluten 0-055 



Fat , 0-056 



Gum 0-020 



Asparagin 0'063 



Extractive 0-921 



Chloride of potassium 0-176 



Silicate, phosphate, and citrate of iron, manganese, alumina, soda, pot- \ 



ash, and lime (of these, potash and citric acid are the prevailing > O'SIS 



ingredients) ; 



Free citric acid 0'047 



100-000 



The sweet potato, so largely used in the United States, 

 contains more water, and about half the proportion of starch 



1 PEREIRA, Treatise on Food and Diet, New York, 1843, p. 180. 



