But in reference to the subject under consideration, practically everything of really effective value which has been advanced by Fletcher was known long before his time. I find that in 1891 Professor John Good-fellow, of the Bow and Bromley Institute, made a special study of the secretion and function of the saliva, the results of which were reported in the Vegetarian for June of that year. He found that in 50 grains of dry wheat-bread, thoroughly masticated and insalivated for sixty seconds, 10 per cent. of the contained starch was converted into maltose and dextrin, whereas when moistened and only masticated for fifteen seconds - which is the average time allowed for moist foods by the fairly careful eater - only 2 per cent. of the contained starch was converted into maltose and dextrin. His next experiment consisted in the mastication for five seconds of 100 grains of oatmeal-porridge mixed with milk and cane sugar, and the determination of its effect on the contained starch. He discovered that it was practically nil, not more than one-half per cent. being converted. He therefore concluded that very little of the starch of our food is converted into sugar in the mouth during ordinary mastication, pointing to the fact that the function of the saliva is to moisten the buccal cavity and facilitate the formation of a bolus.

His further experiments included some made on raw starch in uncooked grain, and of this only an insignificant portion was converted into maltose and dextrin. Dr. Densmore, who quotes these cases, falls into the error of imagining that no starch digestion takes place in the stomach because the alkaline saliva is neutralised and its functions destroyed by the acid gastric juice. On this he founds the argument that food fruits, e.g., figs, which contain as much as 68 per cent. of glucose, should be eaten in preference to bread and other starchy foods. We now know, of course, that for quite an hour, or even in some cases longer, the diastatic action of the saliva continues to be exercised in the stomach. These results are in accordance with those obtained at Battle Creek Sanitarium in the daily examinations in the laboratory.

Two points emerge prominently from this statement: - (1) that from the point of view of the amylolytic effect of saliva during thorough mastication and insalivation Mr. Fletcher was by no means first in the field, (2) that effective mastication has a powerful influence on the digestion of starch in the mouth, but this is not nearly so great as is supposed. Mr. Fletcher, in his powerful advocacy of the practice associated with his name, gives one the impression that all the starch in the food is converted into maltose, and that its digestion is capable of being completed in the mouth, thus giving the pancreas infinitely less work to do and clearing the way for the better digestion of protein in the stomach. But it is evident that this is not the case, and that at any rate in the present evolutionary stage of gastric digestion the stomach has a function to perform in the digestion of carbohydrates.

It is possible - one is safe to say absolutely certain - that the average man is guilty of neglect in mastication, but this appears to be a matter of insignificant importance with a vigorous, healthy digestion. When, however, from any cause this has been lost, thorough mastication is of infinite value, not only because it brings about complete subdivision of the food into particles minute enough to be easily dissolved by the various digestive fluids, but because it is maintained by many that the greater the amount of effective saliva which is secreted, the greater will be the proportion of gastric juice. It is known that alkalis stimulate the secretion of acid - although Pavlov teaches that it is not the alkali but the water in which it is dissolved that excites the secretion - and on this footing alone a more effective gastric juice would be secreted. But it is not at all impossible that absorption of maltose takes place from the stomach in fair proportions, and that this has the effect of an internal secretion in stimulating the secretion of the chemical juice of Pavlov. I frankly admit that the evidence in favour of such a hypothesis is scanty in the extreme, although there is a certain amount of warrant for the statement that sugar in minute proportions is absorbed from the stomach. It is further known that the larger the quantity of gastric juice, the greater will be the quantity of pancreatic fluid, bile, and intestinal secretions; and if the observation is reliable that the saliva is not destroyed in the stomach, but its action only inhibited, and that it is reactivated in the intestine, the total digestive power from all the secretions will thus be strengthened by effective mastication and insalivation. Thus the healthy man can ensure the retention of his vigorous digestion and the dyspeptic has an equal certainty of increasing the chance of its restoration by careful chewing.

To encourage this inestimable practice it is important to consume at each meal a sufficiency of dry food, e.g., toast, or better still zwieback, because of its contained dextrin. Pavlov's experiment demonstrated the fact that dryness of food is the property which above all others stimulates the secretion of saliva. He measured the amount of saliva produced by holding a marble in the mouth, then converted the marble into dust, returned it to the mouth and again measured the quantity of saliva secreted, finding a very large increase.

An ounce of dry-flakes, according to Kellogg, when chewed in portions during five minutes, is capable of giving rise to the secretion of 3 ounces of saliva, whereas moist food evokes a very small secretion indeed. It is also known that the act of chewing itself is responsible for an outflow of saliva, for chewing food on one side only will cause a secretion of three times more saliva on that side than on the other.