706 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



for many body cells, as before stated. These substances may be 

 markedly increased by the usual processes of immunization. Those 

 substances which have the power to produce lysins are called lysinogens 

 and are distinct antigens. The lysins are antibodies. The lysins may be 

 prepared by injecting the experimental animal with the live cells, the 

 dead cells, the disintegration products of cells and in some cases with the 

 metabolic products of cells. 



The Structure of Lysins. Lysins and bactericidal substances have 

 been shown to be composed of two distinct parts: one a thermolabile 

 part known as the complement which is destroyed at a temperature of 

 55 to 60 for thirty minutes; and another part which is thermo- 

 stable, known, on account of its double combining ability, as an ambocep- 

 ior. This amboceptor will withstand heating to 60 for twenty-four 

 hours but if the temperature is raised to 70 it is readily destroyed. If 

 kept at ordinary room temperature or in the ice box amboceptors will 

 remain active for years. According to Ehrlich, amboceptors are the 

 free chemical receptors of the body cells. They are produced in the 

 same way as antitoxins but differ from these bodies in that they have 

 two combining groups, one known as the cytophile group with which 

 the amboceptor combines with the bacteria or other cells, and the other 

 known as the complementophile group, with which it combines with 

 the complement. The complement seems to be a normal constituent 

 of the blood serum and other body fluids. It is undoubtedly produced 

 by the various body cells (leucocytes et al.) and during the immuniza- 

 tion of animals with certain antigens it is probably increased only 

 slightly, if any, in amount. The complement is supposed to be com- 

 posed of two groups also, one a haptophore with which it combines 

 with the amboceptor, and another a zymophore which readily produces 

 the lytic action after the haptophore has combined with the ambocep- 

 tor. On heating the complement the zymophore group is destroyed 

 and a complementoid is produced. This substance is similar to a toxoid 

 and will combine with amboceptor but no lysis will result. It is, 

 however, the amboceptor, or so-called immune body, that undergoes 

 the decided increase during the processes of immunization. It can be 

 accurately demonstrated that the amboceptor must combine with the 

 cell in question before the complement can combine. Cells, such as 

 bacteria or erythrocytes, may be saturated with amboceptor and 

 washed and when the complement is added and combined, lysis takes 



