71 
IMMUNITY- 
Xatural. 
Inherited. 
Acquired : 
Active. 
Passive. 
Toxin immunity: 
Toxemia. 
Antitoxins. 
Bacterial immunity: 
Bacteriemia. 
Bacteriolysins. ’ ' 
Theories explaining immunity: 
A. Alexins, or bactericidal substances in the blood. 
Nuttall and Buchner. 
B. Chemical theory — Ehrlich’s side chains. 
Antitoxin immunity: 
Receptors. 
Toxin — 
Ilaptophore group. 
Toxophore group. 
Cytolytic immunity. 
1. Complement, alexin or cytase; normally present, not specific for species, 
thermolalnle. 
2. Immune l)ody, amboceptor, intermediary body, sensitizer, fixative, pre- 
parative, additive, desmon. 
Produced by process of immunization, specific and therniostabile. 
■ C. Biological theory — phagocytosis of Metchnikoff. 
Ameboid motion. 
Digestive vacuoles — formation of acid. 
Phagocytes: 
Free phagocytes — 
Microphages— 
Polymorphonuclear neutrophiles. 
Eosinophiles. 
Macrophages — 
Large mononuclear lymphocytes. 
. Transitional forms. 
Ej)ithelioid cells. 
Fixed phagocytes — 
Connective tissue corpuscles. 
Vascular endothelium. 
Kuj)fer’s cells, etc. 
Small lymphocytes and mast cells lack ameboid motion and are not phagocytic. 
Chemotaxis — 
Positive. 
Negative. 
D. Enzyme theory — immunizing proteid of Emerich and E'3w. 
Ik Retention theory. 
F. Exhaustion theory. 
