FOODS. 323 



1000 parts, 79 of proteids, 637 of starch, and from 50 to 87 

 of fats; much more than any other kind of grain. Rice is 

 poor in proteids (5G parts in 1000) but very rich in starch 

 (823 parts in 1000). Peas and leans are rich in proteids 

 (from 220 to 260 parts in 1000), and contain about half their 

 weight of starch. Potatoes are a poor food. They contain a 

 great deal of water and cellulose, and only about 13 parts of 

 proteids and 154 of starch in 1000. Other fresh vegetables, 

 as carrots, turnips, and cabbages, are valuable mainly for the 

 salts they contain ; their weight is mainly duQ to water, and 

 they contain but little starch, proteids, or fats. Fruits, like 

 most fresh vegetables, are mainly valuable for their saline 

 constituents, the other foodstuffs in them being only present 

 in small proportion. Some fruit or vegetable is, however, a 

 necessary article of diet ; as shown by the scurvy which used 

 to prevail among sailors before fresh or canned vegetables 

 and lime-juice were supplied to them. 



The Cooking of Vegetables. This is of more importance 

 even than the cooking of flesh, since in most the main ali- 

 mentary principle is starch, and raw starch is difficult of 

 digestion. In plants starch is nearly always stored up in the 

 form of solid granules, which consist of alternating layers of 

 starch cellulose and starch yranulose. The digestive fluids 

 turn the starch into sugars which are soluble and can be 

 absorbed from the alimentary canal, while starch itself can- 

 not. These fluids act slowly and imperfectly on raw starch, 

 and then only on the granulose; but when boiled, the starch 

 granules swell up, and become more readily converted into 

 sugars, and the starch cellulose is so altered that it too un- 

 dergoes that change. When starch is roasted it is in part 

 turned into a substance known as soluble starch which is read- 

 ily dissolved in the alimentary canal. There is, therefore, a 

 scientific foundation for the common belief that the crust of 

 a loaf is more digestible than the crumb, and toast than ordi- 

 nary bread. 



Alcohol. There are perhaps no common articles of diet 

 concerning which more contradictory statements have been 

 made than alcoholic drinks. This depends upon their pe- 

 culiar position: according to circumstances alcohol may be a 

 poison or be useful; when useful it may be regarded either 

 as a force-regulator or a force-generator. It is sometimes a 

 valuable medicine, but it does no good to the healthy body. 



