STOMACH AND INTESTINE. 



393 



value and importance assigned to this variety of 

 azotized aliment amongst rural populations 

 where meat is .scarce and expensive. Indeed, 

 the diet on which tradition states old Parr to 

 have attained his remarkable age can hardly 

 have been very unwholesome. And the 

 natives of a country which, like ours, still 

 boasts of large cheese-fairs in some of its 

 country towns, can find little to wound their 

 national pride in the quaint fancy of Mueller : 

 that cheese and freedom flourish together. 



Vegetable food. The general characters 

 of vegetable food have already been alluded 

 to. They are, however, modified by all cir- 

 cumstances which materially affect the ar- 

 rangement or composition of the vegetable 

 tissues. Thus young plants, or the younger 

 shoots of plants, are much more easily digested 

 than the harder and less soluble textures 

 of the older organism. While the approach 

 of fruits towards their maturity determines 

 a series of physical and chemical alterations, 

 which have the result of rendering them much 

 more nutritious. The mode of culture, and 

 the peculiarities of the soil, also exercise im- 

 portant influences on the resulting vegetable 

 produce. Thus a rich soil, a warm climate, 

 or a highly azotized manure, have all been 

 noticed to increase the per-centage of protein 

 contained in the corn grown under their in- 

 fluence. And the influence of such circum- 

 stances will, of course, be in some degree 

 extended to the persons and animals, whose 

 staple food is thus partially dependent upon 

 them. 



Corn. The seeds of the cerealla are not 

 only the most important of all the varieties of 

 vegetable food, but may even be ranked above 

 all other alimentary substances, animal as well 

 as vegetable. The history of mankind suffi- 

 ciently attests the truth of this estimate, 

 an estimate which is confirmed by the appel- 

 lation of " the staff of life," that is applied to 

 their chief product as prepared for food. 



An inquiry into their composition explains 

 this remarkable value, by showing that the 

 nutriment which such seeds place at the dis- 

 posal of the vegetable embryo they contain, 

 has a close resemblance to milk, both in the 

 number and proportion of the alimentary 

 principles of which it is composed. 



The proteinous constituent of all the cereal 

 grains forms a considerable proportion of their 

 total weight. In wheat it even reaches 22 

 per cent, of the dried mass. But in rye, 

 barley, oats, and maize, this amount is dimi- 

 nished to about 15 per cent. And in rice and 

 buckwheat, it may be estimated at not more 

 than 7 per cent. In respect to the varieties 

 of protein which are present, we find sub- 

 stances resembling all three of its chief modi- 

 fications in the animal kingdom. Thus wheat 

 contains a large quantity of vegetable gluten, 

 and vegetable fibrin, which are respectively 

 analogous to casein and fibrin ; together with 

 a small portion of vegetable albumen. 



The amylaceous or starchy constituent, 

 which represents the calorific elements of the 

 food, also varies in quantity ; but to a smaller 



degree than does the protein. It forms about 

 two-thirds of the four first kinds of grain above 

 mentioned. In maize and rice, however, it 

 rises to about 78 and 86 per cent, respectively ; 

 apparently replacing the protein which is 

 diminished here. This starch is associated 

 with a variable quantity of sugar, part of 

 which may probably be regarded as produced 

 from its own metamorphosis. And gum is 

 also present in small quantity. 



The hydrocarbons are only represented by 

 a small quantity of fatty and resinous matter; 

 the greater part of which, together with the cel- 

 lulose also present, passes through the alimen- 

 tary canal without undergoing any digestion. 



The salts found in the ash generally make 

 up about 1 to 3 per cent, of the whole vege- 

 table mass. As regards their bases, they are 

 chiefly characterized by containing little lime 

 in comparison with magnesia. The quanti- 

 ties of potash and soda experience great fluc- 

 tuations : which are probably connected 

 with the natural or artificial peculiarities of the 

 soil in which the corn has been grown. The 

 quantity of iron is generally considerable. 

 As regards the acids of these salts, the phos- 

 phoric greatly predominates ; while the sul- 

 phuric is in but small quantity. And the 

 chlorides, so important to digestion and nu- 

 trition, are almost absent. 



The ordinary preparation of these different 

 kinds of grain is such as to introduce some 

 slight changes of composition. The grinding 

 of corn into flour strips away the outer husk 

 of the grain ; and thus has the disadvantage of 

 removing a part of it, which contains a much 

 larger proportion of protein than its more 

 starchy interior. The subsequent process of 

 fermentation and baking converts part of 

 the starch into sugar and alcohol, with the 

 formation of carbonic acid gas. The slow 

 extrication of this elastic fluid gives the bread 

 a porous or spongy character; which has the 

 advantage of greatly increasing the effective 

 surface that is subsequently exposed to the 

 action of the digestive fluids. Part of the 

 gluten of the flour is also lost in the process. 

 But the whole amount of both gluten and 

 starch which disappears is not very consi- 

 derable; probably not more than 5 per cent. 

 This trifling loss, and the addition of about 

 30 per cent, of water, constitute almost the 

 only noticeable differences between the com- 

 position of pure wheaten bread, and that of 

 the flour from which it is made. Their effect 

 is, to exchange the composition already men- 

 tioned in speaking of wheat, for about 16 per 

 cent, of protein, and 35 to 40 of starch, in 

 bread of a moderate dryness. But the advan- 

 tages afforded by the spongy texture, and the 

 intimate admixture of water, which are 

 brought about in the process of making bread, 

 are still further increased by a mechanical 

 change produced in the starch-granules 

 themselves. For, under the influence of the 

 moisture to which they are exposed, most of 

 these swell up and burst, and thus place their 

 contents in a state much more accessible to 

 the changes which are subsequently induced 



