LECTURE I.

The general nature of Proteolytic Enzymes and of Proteids.

Introductory observations,[1]
Early history of gastric digestion,[3]
The proteolytic power of the pancreatic juice,[7]
The general nature of proteolytic enzymes,[8]
Origin of proteolytic enzymes,[8]
Preparation of pepsin,[10]
Reactions and composition of proteolytic enzymes,[13]
The proteid nature of enzymes,[15]
Conditions modifying the action of enzymes,[17]
The influence of temperature on proteolytic action,[18]
The influence of acids, alkalies, and other substances on the activity of enzymes,[20]
Action of chloroform on pepsin,[21]
Theories of enzyme action with special reference to catalysis,[22]
The general nature of Proteids,[27]
Classification of proteids,[29]
Chemical composition of some of the more prominent proteids occurring in nature,[31]
Chemical constitution of proteids,[33]
The presence of hemi- and anti-groups in all typical proteids,[34]
Cleavage of the albumin-molecule with dilute sulphuric acid,[34]
Hydration and cleavage of albumin by the action of superheated water, with formation of atmid-albumoses, etc.,[37]
Action of powerful hydrolytic agents on proteid matter,[39]
Initial action of pepsin-acid on proteids,[40]
Scheme of the general line of proteolysis as it occurs in pepsin-digestion, with a view to the structure of the albumin-molecule,[41]

LECTURE II.

Proteolysis by pepsin-hydrochloric acid, with a consideration of the general nature of proteoses and peptones.

Proteolysis by pepsin-acid,[44]
Formation of hydrochloric acid in the gastric glands,[45]
Liebermann’s theory regarding the formation of the acid of the gastric juice,[46]
Differences in the action of free and combined acid,[47]
Proteolysis in the presence of combined acid,[49]
The combining power of various forms of proteid matter with hydrochloric acid,[51]
Quantitative estimation of the affinity of the products of digestion for acid,[53]
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]
Proteose-like nature of the poisons produced by bacteria,[89]
The acrooalbumoses formed by the tubercle-bacillus,[90]
Toxic nature of proteoses and peptones,[91]

LECTURE III.

Proteolysis by trypsin—Absorption of the main products of proteolysis.