THE CHEMISTRY OF COOKERY. 823 



by other means of which I shall have to speak more fully hereafter 

 when I come to the cookery of vegetables. When simply heated, it 

 is converted into dextrin or " British gum," largely used as a substi- 

 tute for gum-arabic. If the heat is continued a change of color takes 

 place ; it grows darker and darker until it blackens just as sugar 

 does, the final result being neai'ly the same. Water is driven off in 

 both cases, but in carbonizing sugar we start with more water, sugar 

 being starch plus water or the elements of water. Thus the brown 

 material of bread-crust or toast is nearly identical with caramel. 



I have often amused myself by watching what occurs when toast- 

 and-water is prepared, and I recommend my readers to repeat the 

 observation. Toast a small piece of bread to blackness, and then float 

 it on water in a glass vessel. Leave the water at rest, and direct 

 your attention to the under side of the floating toast. Little thread- 

 like streams of brown liquid will be seen descending in the water. 

 This is a solution of the substance which, if I mistake not, is a sort of 

 caramel, and which ultimately tinges all the water. 



Some years ago I commenced a course of experiments with this 

 substance, but did not complete them. In case I should never do so, 

 I will here communicate the results attained. I found that this starch 

 caramel is a disinfectant, and that sugar caramel also has some disin- 

 fecting properties. I am not prepared to say that it is powerful 

 enough to disinfect sewage, though at the time I had a narrow escape 

 from the Great-Seal Office, where I thought of patenting it for this 

 purpose as a non-poisonous disinfectant that may be poured into rivers 

 in any quantity without danger. Though it may not be powerful 

 enough for this, it has an appreciable effect on water slightly tainted 

 with decomposing organic matter. 



This is a very curious fact. We do not know who invented toast- 

 and-water, nor, so far as I can learn, has any theory of its use been 

 expounded, yet there is extant a vague, popular impression that the 

 toast has some sort of wholesome effect on the water. I suspect that 

 this must have been originally based on experience, probably on the 

 experience of our forefathers or foremothers living in country places 

 where stagnant water was a common beverage, and various devices 

 were adopted to render it potable. 



Gelatine, fibrine, albumen, etc. i. e., all the materials of animal 

 food as already shown, are composed, like starch and sugar, of car- 

 bon, hydrogen, and oxygen, with, in the case of these animal sub- 

 stances, the addition of nitrogen ; but this does not prevent their 

 partial carbonization (or " caramelizing," if I may invent a name to 

 express the action which stops short of blackening). Animal fat is 

 a hydrocarbon which may be similarly browned, and, if I am right in 

 my generalization of all these browning processes, an important prac- 

 tical conclusion follows, viz., that cheap soluble caramel made by skill- 

 fully heating common sugar, is really, as well as apparently, as valuable 



