We now know that this idea of decomposing water by such means is a mistake; but, in my own opinion, there is something behind it which still remains to be learned by modern chemists. In my endeavours to fathom the _rationale_ of the changes which occur in cookery, I have been (as my readers will remember) continually driven into hypotheses of hydration, _i.e._ of supposing that some of the water used in cookery unites to form true chemical compounds with certain of the constituents of the food. As already stated, when I commenced this subject I had no idea of its suggestiveness, of the wide field of research which it has opened out. One of these lines of research is the determination of the nature of this hydration of cooked gelatin, fibrin, cellulose, casein, starch, legumin, &c. That water is _with_ them when they are cooked is evident enough, but whether that water is brought into actual chemical combination with them in such wise as to form new compounds of additional nutritive value proportionate to the chemical addition of water, demands so much investigation that I have been driven to merely theorise where I ought to have demonstrated. The fact that the living body which our food is building up and renewing contains about 80 per cent. of water, some of it combined, and some of it uncombined, has a notable bearing on the question. We may yet learn that hydration and dehydration have more to do with the vital functions than has hitherto been supposed. The following are the ingredients used by Rumford in ‘Soup No. 1’: Weight Avoirdupois. Cost. lbs. oz. £ s. d. 4 _viertels_ of pearl barley, equal to about 20⅓ gallons 141 2 0 11 7½ 4 _viertels_ of peas 131 4 0 7 3¼ Cuttings of fine wheaten bread 69 10 0 10 2¼ Salt 19 13 0 1 2½ 24 _maass_, very weak beer, vinegar, or rather small beer turned sour, about 24 quarts 46 13 0 1 5½ Water, about 560 quarts 1,077 0 -- --------- --------- 1,485 10 1 11 9