So separated, the peptone formed in gastric digestion is exceedingly gummy, but can be transformed into a yellowish powder, very hygroscopic, of more or less bitter taste, and, when thoroughly dry, dissolving in water with a hissing sound and with considerable development of heat, like phosphoric anhydride.[119] [119] Kühne and Chittenden: Peptones. Studies in Physiol. Chem., Yale University, vol. 2, p. 14. I have introduced these dry chemical facts, none of which are especially new, because I deem them of considerable importance and because they are not very generally known. In fact, there seems to be a tendency on the part of some who are more or less familiar with the advances made in our knowledge of the products of pepsin-proteolysis to question the existence of these different bodies, or to show at least a spirit of indifference toward these recent facts which have been gradually accumulated, and I may say accumulated at the expense of considerable labor. The time is past for calling the products of gastric digestion peptones; it is time for a full recognition of the fact that pepsin-proteolysis is synonymous with the production of a row of bodies, chemically and physiologically distinct from each other, each endowed with individuality enough to admit of certain detection, and all bearing a certain specific and harmonious relationship to their neighbors, the other members of the series. Further, it is not enough to admit the formation of a single intermediate body, midway between syntonin and peptone. The so-called propeptone of the past is simply a mixture of proteoses, of ever changing composition, varying with each change in the proportion of the component proteoses. Each of these proteoses can be detected, under suitable conditions, in the products of every artificial digestion as well as in the stomach-contents, and no better measure of the proteolytic power of the natural stomach-secretion can be devised than a study of the character of the individual bodies present in the stomach-contents after a suitable test meal. The proper tests and separations can be made with a small amount of the filtered fluid, and much light thrown upon the digestive power of the secretion by even a rough estimate of the proportion of primary and secondary proteoses and peptones formed in a given time, after the ingestion of a certain amount of proteid food.