Mrs. Lincoln's Boston cook book

' ' This saliva is poured into the mouth not to he cast out, but to do a specific work, then pass into the stomach and be again absorbed. If the system be drained of the saliva by profuse spitting, as is the case with those who use tobacco freely, the order of bodily functions is reversed, and the mouth is made to do the work of the kidneys, which is to carry away a large amount of the superfluous water and all the waste salts." The Boston Cook Book The saliva consists mostly of water, with a very small amount of saline matter and about five parts in one thousand of ptyalin, an albuminous ingredient, or ferment, which has the power of converting the starchy portions of food into sugar, and sugar into lactic acid, but does not act upon nitrogenous food. The saliva froths easily, and aids in carrying air into the stomach. This is the first step in digestion, and the most important, as any error in the beginning leads to evil consequences which affect the whole process. It is also important, because it is wholly a voluntary process. While the food is in the mouth, we may masticate it thoroughly or imperfectly, and swallow or reject it. But when deglutition has carried it into the stomach, it is wholly beyond our control, and we are not responsible for the remainder of the process, only so far as it may be affected by error in the first stages. Bread, potatoes, and all starchy foods should be thoroughly masticated, and mingled with the saliva. Meat may be swallowed hastily, or knives may be made to do the work of the teeth in masticating animal food; but no chemist can prepare an artificial saliva to be mixed with starchy food, to save the trouble of chewing it. If a piece of dry light bread be masticated thoroughly, it will crumble and be quickly mixed with the saliva, and become sweeter the longer it is kept in the mouth. The alkaline saliva changes the starch into sugar, and begins the digestion. Try to chew a piece of hot bread and it at once assumes a pasty condition, which neither teeth nor saliva can penetrate, and is swallowed involuntarily. A piece of putty would not be more indigestible. If this experiment be tried, no other argument would be needed against the use of hot bread. The stomach carries on the second part of digestion. The presence of food excites the flow of a fluid called the gastric juice j which is secreted in large quantities in the mucous membrane of the stomach. At the same time the muscular coats of the stomach contract, and produce a sort of churning motion, which carries the food round and round and over and over, exposing all parts of it to the action of the fluid. This gastric juice is always decidedly aczJ in its nature, containing hydrochloric acid. The lactic acid formed from the sugar in the mouth is also present in the stomach. This acid arrests the work begun in the mouth on the starchy foods, renders the alkali neutral, and acts only on albuminous food. It contains an albuminous ingredient, or ferment, called pepsin, in^aboutthe same proportion as the ptyalin of the saliva. The pepsin The Boston Cook Book. All