78o THE POPULAR SCIENCE MONTHLY. 



m'enu. When we eat raw vegetables, as in salads, we obtain all their 

 potash. 



Fruits generally contain important quantities of potash salts, and 

 it is upon these especially that the possible victims of lithic acid should 

 rely. Lemons and grapes contain them most abundantly. Those who 

 can not afford to buy these as articles of daily food may use cream of 

 tartar, which, when genuine, is the natural salt of the grape, thrown 

 down in the manner I shall describe when on the subject of the cook- 

 ery of wines. 



At the risk of being accused of presumption, I must here protest, 

 as a chemist, against one of " the fallacies of the faculty," or of cer- 

 tain members of the faculty, viz., that of indiscriminately prohibiting 

 to gouty and rheumatic patients the use of acids or anything having 

 an acid taste. 



This has probably arisen from experience of the fact that nimeral 

 acids do serious mischief, and that alkaline carbonate of potash affords 

 relief. The difference between the organic acids, which are decom- 

 posed in the manner I have described, and the fixed composition of 

 the mineral acids does not appear to have been sufficiently studied by 

 those who prohibit fruit and vegetables on account of their acidity. 

 It must never be forgotten that nearly all the organic compounds of 

 potash, as they exist in vegetables and fruit, are acid. It may be de- 

 sirable, in some cases, to add a little bicarbonate of potash to neutral- 

 ize this excess of acid and increase the potash-supply. I have found 

 it advantageous to throw a half-saltspoonful of this into a tumbler of 

 water containing the juice of a lemon, and have even added to it 

 stewed or baked rhubarb and gooseberries. In these it froths like 

 whipped cream, and diminishes the demand for sugar, an excess of 

 which appears to be mischievous to those who require much potash. 



I must conclude this sermon on the potash text by adding that it 

 is quite possible to take an excess of this solvent. Such excess is de- 

 pressing ; its action is what is called " lowering." I will not venture 

 upon an explanation of the rationale of this lowering, or discuss the 

 question of whether or not the blood is made watery, as sometimes 

 stated. 



Intimately connected with this part of my subject is another vege- 

 table principle that I have not yet named. This is vegetable jelly, 

 or pectin, the jelly of fruits, of turnips, carrots, parsnips, etc. Fremy 

 has named it pectose. It is so little changed by cookery that I need 

 say little about it beyond stating the fact that an acid may be sepa- 

 rated from it which has been named pectic acid, the properties and 

 artificial compounds of which appear to me to suggest the theory 

 that the natural jelly of fruits largely consists of pectites of potash 

 or soda or lime. We all know the appearance and flavor of currant- 

 jelly, apple- jelly, etc., which are composed of natural vegetable jelly 

 plus sugar. 



