PRELIMINARY REMARKS ON IMMUNITY IN THE ANIMAL KINGDOM 40
Examples of natural immunity among the Invertebrates.—Immunity
against micro-organisms and insusceptibility to microbial
poisons are two distinct properties.—The refractory organism
does not eliminate micro-organisms by the excretory channels.—It
destroys them by a process of resorption.—The fate of foreign
bodies in the organism.—The resorption of cells.—Intracellular
digestion.—This digestion effected by the aid of soluble
ferments.—Digestion in Planarians and
Actinians.—Actinodiastase.—Transition from intracellular
digestion to digestion by secreted juices.—Digestion in the
higher animals.—Enterokynase and the part it plays in
digestion.—The psychical and nervous elements in
digestion.—Adaptation of the pancreatic secretion to the kind of
food.—Excretion of pepsin in the blood and in the urine.