Richet’s theory regarding the conjugate character of the acid of the gastric juice, 54 Proteolysis in the presence of amido-acids, 55 Necessity for knowing the amount of combined acid in the stomach-contents, 57 Antiseptic action of the hydrochloric acid of the gastric juice, 58 The maximum action of pepsin exerted only in the presence of free hydrochloric acid, 59 Division of the products of pepsin-proteolysis into three main groups, 60 Detection of the products of digestion, 61 Separation of proteoses and peptones from a digestive mixture or from the stomach-contents, 62 Some of the chemical properties of peptones, 64 The so-called propeptone a mixture of proteoses, 65 Pepsin-proteolysis synonymous with a series of progressive hydrolytic changes, 66 Chemical composition of proteoses and peptones, 67 Pepsin-proteolysis a true hydrolytic and cleavage process, 71 Schützenberger’s results on the formation of fibrin-peptone, 72 Amphopeptones the final products of gastric digestion, but proteolysis never results in complete peptonization, 73 Solution of a proteid by pepsin-acid not synonymous with peptonization, 75 Influence of the removal of the products of digestion on the activity of the ferment, 75 Lack of complete peptonization by pepsin-acid not due to accumulation of the products of digestion, 76 The diffusibility of proteoses and peptones, 77 Absorption of peptones from the living stomach, 79 Differences between natural digestion in the stomach and artificial proteolysis, 80 Relative formation of proteoses and peptones in the living stomach, 81 Gastric digestion merely a preliminary step in proteolysis, 81 Intestinal digestion alone capable of accomplishing all that is necessary for the complete nourishment of an animal, 82 Some physiological properties of proteoses and peptones, 83 The experiments of Schmidt-Mülheim and Fano on the action of peptones when injected into the blood, 84 Physiological action of albumoses, 85 Introduction of albumoses into the blood, 87