Page:Popular Science Monthly Volume 25.djvu/658

642 in a weak solution of bicarbonate of potash for two or three hours, a partial solution of the casein is effected, producing pease-pudding, or pease-porridge, or puree (according to the quantity of water used), which is softer and more gelid than that which is obtained by similarly boiling without the potash. The undissolved portion evidently consists of the fibrous tissue of the peas, the gelatinous or dissolved portion being the starch, with more or less of casein. I say "more or less," because, at present, I have not been able to determine whether or not the casein is all rendered soluble. The flavor of the clear pea-soup, which I obtained by filtering through flannel, shows that some of the casein is dissolved; this is further demonstrated by adding an acid to the clear solution, which at once precipitates the dissolved casein. The filtered pea-soup sets to a stiff jelly on cooling, and promises to be a special food of some value, but, for the reasons above stated, I am not yet able to speak positively as to its practical value. The experience of any one person is not sufficient for this, the question being, not whether it contains nutritive material—this is unquestionable—but whether it is easily digested and assimilated. As we all know, a food of this kind may "agree" with some persons and not with others—i.e., it may be digested and assimilated with ease or with difficulty according to personal idiosyncrasies. The cheesy character of the abundant precipitate, which I obtain by acidulating this solution, is very interesting and instructive, regarded from a chemical point of view. The solubility of the casein is increased by soaking the peas for some hours, or, better still, a few days, in the solution of bicarbonate of potash.

Another question is opened by these experiments, viz.: What is the character and the value of the fibrous solid matter remaining behind after filtering out the clear pea-soup? Has the alkali acted in an opposite manner to the acid in the ripening pear? Is it merely a fibrous refuse only fit for pig-food, or is it deserving of further attention in the kitchen? Should it be treated with dilute acid—say a little vinegar—to break up the fiber, and thereby be made into good porridge? Other questions crop up here, as they have been cropping continually since I committed myself to the writing of these papers, and so abundantly that, if I could afford to set up a special laboratory, and endow it with a staff of assistants, there would be some years* work for myself and staff before I could answer them exhaustively, and doubtless the answers would suggest new questions, and so on ad infinitum. I state this in apology for the merely suggestive crudity of many of the ideas that I throw out in the course of these papers.

Before leaving the subject of peas, I must here repeat a practical suggestion that I published in "The Birmingham Journal" about twenty years ago, viz., that the water in which green peas are boiled should not be thrown away. It contains much of the saline