394 



STOMACH AND INTESTINE. 



in them by the salivary and pancreatic secre- 

 tions. 



The various leguminous seeds contain a 

 quantity of the protein-compounds which may 

 be estimated as forming, on an average, nearly 

 30 per cent, of their weight ; or half as much 

 again as that present in the cerealia. The 

 quantity of their starchy constituent is, how- 

 ever, much less ; being barely 40 per cent. 

 They contain a somewhat larger quantity of 

 gum. They have also a larger (3) per centage 

 of saline ash ; the several ingredients of which, 

 though almost identical with those of the 

 cerealia, approach each other much more nearly 

 in quantity. From the few analyses hitherto 

 made, it would appear that the quantity of 

 alkaline bases is very large : but that potash pre- 

 dominates over soda ; and lime nearly equals 

 magnesia. And though the phosphoric is still 

 the predominant acid, sulphuric and hydro- 

 chloric are also combined with the above 

 bases : the latter chiefly with soda. 



The value of these vegetables as food will 

 of course depend on the preparation to which 

 they have been subjected before being eaten. 

 When ripe and dried, their small proportion 

 of water, and their great density, together with 

 the little surface they expose, together render 

 them almost impregnable to the attacks of the 

 various digestive agents. And even after 

 moderate mastication, their larger fragments 

 pass with little change through the whole of 

 the intestinal human canal. 



But after careful boiling, which bursts their 

 starch granules, dissolves their gum, and 

 softens and breaks up their various tissues, 

 they assume the proper digestive value to 

 which their composition entitles them. So 

 prepared for eating, their large constituent 

 of vegetable casein renders them a most 

 efficacious azotized food. While their con- 

 siderable quantity of starch, as well as their 

 comparatively uniform admixture of the par- 

 ticular salts most important to nutrition, 

 gives them a completeness for dietetic pur- 

 poses, which even wheat can scarcely be said 

 to possess. Hence we are entitled to sup- 

 pose that, if suitably prepared by cooking, 

 some of these legumes might form a food 

 sufficient for the maintenance of health. * 

 At any rate, we may presume, that their 

 dietetic usefulness is rather under than over- 

 rated ; so that, on physiological grounds, their 

 consumption as human food might be advan- 

 tageously extended far beyond those limits 

 which the custom of modern European na- 

 tions (and especially of the English) seems to 

 have assigned them. 



The potato, the starchy tuber of a plant 

 belonging to the poisonous genus of the So- 

 lanece, is an article of vegetable food, the pro- 

 perties of which render it a remarkable con- 

 trast to the preceding group. We may best 

 sum up its average composition as consisting 

 of about 75 per cent, of water, and 25 of 

 solids. Of the latter portion, only one-tenth 



* Compare Daniel, chap. i. verse 12. 



is composed of protein, which is present in 

 the form of albumen and asparagin. Three- 

 fifths of these solids are starch. The salts of 

 its ash amount to about 1 per cent. They are 

 chiefly characterized by the fact, that though 

 they contain little lime, and scarcely any soda, 

 they include a large amount of potash ; 

 which, in the fresh tuber, is probably com- 

 bined with some of the organic acids present. 

 The quantity of phosphates is also very 

 small: barely, one-fourth of that contained 

 in the various cerealia. 



The above sketch of the composition of 

 this vegetable sufficiently entitles the physio- 

 logist to range himself with the economist 

 in determined opposition to the predominant 

 use of this vegetable as the principal arti- 

 cle of food. We may dismiss from our notice 

 all consideration of the social and moral 

 degradation which, since its introduction 

 with this object, have steadily followed such 

 undue use of the potato as the staple ali- 

 ment in various parts of Europe. We may 

 even set aside those fearful outbreaks of 

 pestilence in Ireland which, though produced 

 by the quantitative failure of one crop, must 

 surely have been in some degree fostered 

 by a peculiar state of the constitution itself 

 probably founded, in part, on the qualitative 

 deficiencies of the previous food. Our ob- 

 jections to the potato find a better excuse in 

 such a composition as the above. Rough as 

 is the above estimate, it nevertheless claims to 

 be based upon analyses of unusual number 

 and accuracy. It shows that the food 

 to which it refers is wanting in some of 

 the most important saline constituents of 

 the body; such as the phosphates, which are 

 hourly leaving the organism in comparatively 

 large quantity. And that, in addition to this 

 grave fault, it contains so small a proportion 

 of protein, that we may calculate about thir- 

 teen pounds of potatoes as the quantity 

 which a man ought to take into his stomach, 

 in order to replace the waste of his body by 

 a sufficient quantity of the histogenetic con- 

 stituent of the food. At least this would 

 be the amount corresponding to the protein 

 which long experience has shown to be enough, 

 and not too much, for the daily ration of a 

 soldier : that is, for the food of an adult male, 

 in good health, and habituated to moderate, 

 but not excessive, bodily labour. Lastly, we 

 need hardly add, that the form and arrange- 

 ment of the protein contained in the potato 

 are such as would scarcely ever allow it to be 

 as well digested as the protein contained in 

 the bread and meat of the soldier's ration. 

 Hence its less suitable quality would require 

 to be compensated by a still further increase 

 of quantity.* 



But the mixture of potatoes with other 

 alimentary substances, and especially with 

 meat or milk, removes all these objections, 

 and restores it to its proper rank in the scale 



* A great increase in the capacity of the stomach 

 is regarded by Dr. Todd as a not infrequent result 

 of an almost exclusive potato diet, so common among 

 the lower classes of the Irish. 



