CHAPTER V.. Theory and Laws of Digestion.

THEORY AND LAWS OF DIGESTION.

Different theories of Digestion--Concoction--Fermentation --Putrefaction--Trituration--Chemical solution--Conditions or laws of digestion--Influence of gastric juice.--Experiments illustrative of its solvent power--Its mode of action on different kinds of aliment--beef, milk, eggs, soups, &c.--Influence of temperature--Heat of about 100° essential to digestion.--Gentle and continued agitation necessary--Action of stomach in admitting food--Uses of its muscular motion--Gastric juice acts not only on the surface of the mass, but on every particle which it touches--Digestibility of different kinds of food--Table of results--Animal food most digestible--Farinaceous next--Vegetables and soups least digestible--Organs of digestion simple in proportion to concentration of nutriment--Digestibility depends on adaptation of food to gastric juice more than on analogy of composition--Illustrations.--No increase of temperature during digestion--Dr Beaumont’s summary of inferences, 109–151