Look into a rotisserie window and notice how "it makes your mouth water." Making "your mouth water" is a fact, not a fiction. Psychical influences in stimulating digestion are extremely important, as innumerable experiments have shown. These psychical influences may stimulate digestion by stimulating the secretion of digestive juices - the fluids responsible for so altering the food as to make it fit for absorption by the blood and the system as a whole.

Often enough we get no psychical reaction after surveying the dishes spread on the table. Pot roast may not be a relishing dish to some. To make it more so we may do one of several things.

We may add a little mustard or a little ketchup to our pot roast; or we may eat it with some pickles; or we may add some salt and pepper. Per haps none of these additions serves the purpose. If so, another dish has to be substituted. But very often the mustard or pickles, etc., do help. Any one of these additional substances helps to do what the mere looking at an appetizing dish will do - increase the flow of digestive juices. The primary function of these flavors and condiments is to make the food more appetizing.

Slightly removed from the substances just described are the stimulants, of which tea, coffee, cocoa, meat extracts (beef tea, beef juice, etc.), and, above all, alcohol are examples. They too - particularly alcohol - stimulate the flow of the digestive juices. With some of them, as with tea and coffee, the stimulation is due to the presence of an alkaloid, and alkaloids are distinctly injurious when taken in large quantities; hence the advisability of moderate tea and coffee drinking.

Very few of these substances add much to our calorific needs or to our requirements for tissue repair; though cocoa, with its relatively large quantity of sugar and fat (in the milk), and beer do give appreciable energy values. But notice that the calories are not derived to any extent from the stimulant itself, but from the substances mixed with the stimulant or condiment.