In recent years many other experiments confirming those of Mr. Fletcher have been conducted. At Yale University, five years ago, a band of nine students undertook an experiment to test the virtues of thorough mastication. The experiment was divided into stages, in the first of which the following two rules were observed: -

(1) To masticate thoroughly every morsel of food, with the attention concentrated not upon the mechanical act of chewing, but upon the taste and enjoyment of the food.

(2) To follow implicitly and absolutely the dictates of the appetite both as to the amount and kind of food chosen.

During the second stage a third rule was added, viz.: -

(3) To use reason when instinct was in doubt.

To enable this to be put into operation the foods were divided into two lists, one in the tentative order of intrinsic merit, beginning with the fruits and ending with alcohol, the other in the proportion of their protein-content. The men were then instructed when their appetites were entirely willing to acquiesce, and only then, to select the better and purer foods and those with a low protein-content in preference to those with a high protein-content. Careful physical tests were instituted, and the excreta were examined in the laboratory of the Sheffield Scientific School.

At the conclusion of the experiment the following were the phenomena noted. Whilst there was a slight reduction in the total amount of food consumed, there was a large reduction in the consumption of protein-containing foods, especially flesh foods, a diminished excretion of nitrogen, a reduction in the odour, putrefaction, fermentation, and quantity of the faeces, a slight loss of weight and strength, an enormous increase of physical endurance, and a slight increase in mental alertness. Irving Fisher concludes that there is much evidence in this experiment to show that thorough mastication is "natural" to man, and that its adoption is certain to lessen the consumption of foods containing a large proportion of protein and to encourage the use of those, especially of the fleshless variety, containing less protein. Although Irving Fisher is not a medical man he is recognised to be a careful observer, and I think that he is justified from the evidence in this experiment in concluding that better results in nutrition and endurance are obtained by efficient mastication and thorough insalivation than when these functions are neglected. In this and subsequent experiments at Yale and Brussels it was found that the closer the approach was made to vegetarianism the greater was the endurance, whilst without having any more strength, the vegetarians had by far the greatest endurance of all. Although Fisher does not make the statement specifically, he is inclined to institute a comparison between carnivorous and granivorous or fleshless eating animals in this connection.