642 THE POPULAR SCIENCE MONTHLY, 



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 simi- 

 larly 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 sufiicient for this, the question 

 being, not whether it contains nutritive material — this is unquestion- 

 able — ^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 difliculty according to personal idiosyncrasies. The cheesy char- 

 acter 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 be- 

 hind 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 atten- 

 tion 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 constitu- 



