2. We are acquainted with the fact that the potential energy which is utilised by the animal is supplied to it with the least wear and tear to, or strain upon, its mechanism by non-nitrogenous organic constituents of food which must belong to the groups of starches and sugars or fats, but that the continued existence of the organism demands, as an essential condition, the introduction of a certain proportion of albuminous matter. In spite of numerous very fine investigations on this subject, the yet more precise determination of the minimum quantity of the albuminous constituents which are absolutely necessary or desirable, under the most varying conditions, is eminently desirable, especially in the light of recently recorded facts, amongst which are those to be referred to under 3 (following):— 3. Certain very noteworthy observations made by Messrs. Horace Fletcher and Ernest H. Van Someren have shown that an excessively prolonged mastication and insalivation of food leads to remarkable results in respect to the diminution of the total quantity of food necessary to keep the body in a state of health, and to, as is alleged, a remarkable improvement in the digestive functions as well as of the general health of the individual. It appears highly important thoroughly to investigate the remarkable phenomena discovered by Messrs. Fletcher and Van Someren, and to determine how far they may lead to a modification of or improvement in the dietary of healthy individuals and of persons in a state of disease. 4. Indeed, it may truly be said that the average diet of man, that is to say, the absolute and relative amount of certain food-stuffs on which an average man should live, is at present, to a large extent, determined in an empirical manner. It is most necessary that this should be determined in an exact manner, since it is at least possible that a more complete knowledge may reveal that the good results thus obtained empirically are only reached by means of an excess of one element being counterbalanced by excess of another element, and thus open up a way to considerable economy. The changes needed for variations from the average, to meet certain conditions, are also at present, to a very large extent, determined empirically, and these also most certainly ought to be determined in an absolutely exact manner. 5. The researches of Pawlow on the conditions which influence the activity of the secreting glands of the organs of digestion, upon the relation of their activity to the nature of the food ingested, upon the influence exerted by the secretion of the glands situated in one part of the alimentary canal, upon the activity of glands situated lower down, indicate lines of research only recently opened out, but the importance of which in reference to the problems of nutrition is probably great.