274 MEDICAL BACTERIOLOGY 



It is a natural and common tendency to explain anaphylaxis so as to har- 

 monize it with Ehrlich's theory of immunity: assuming that the first injection 

 or ingestion of antigen does not produce ill effect because it is not toxic as taken 

 in, only becoming toxic when disintegrated; at the time the body receives its 

 first dose of antigen the body cells and fluids are poor in ferments or receptors 

 or both, capable of disintegrating the antigen, hence it is slowly disintegrated, 

 the toxic substance being slowly liberated in quantities too small to irritate; 

 this antigen must be disintegrated (to feed the body or be eliminated) and its 

 presence is a stimulus to the body cells to produce much more ferment and 

 receptors capable of disintegrating antigen and hence capable of liberating its 

 toxic components; this stimulated new activity of the body cells results in a 

 gradual increase of ferments and receptors, the quantity necessary to disinte- 

 grate antigen so rapidly as to liberate at once sufficient toxin to produce obvious 

 injury, does not develop or accumulate until one or more weeks after the stimulus 

 to production caused by the first dose of antigen; a second injection of antigen 

 given in the early days of increased antibody production (period of incubation) 

 does not produce ill effect for the same reason that the primary does not; a 

 second injection of antigen given when antibody production has reached its 

 maximum (period of hypersensitiveness) produces ill effect because it is rapidly 

 disintegrated and therefore an injurious quantity of toxin suddenly liberated; 

 animals that survive this injury, by it have their cells stimulated to form recep- 

 tors or ferments for the toxic component liberated when antigen is disintegrated, 

 hence subsequent doses of antigen do not produce ill effect (the animal has lost 

 its hypersensitiveness, is immune) because there are antibodies in the animal's 

 blood serum that neutralize the toxin as fast as it is liberated by disintegration 

 of antigen. This explanation is largely hypothetical. 



RELATIONSHIP OF ALLERGY, ANAPHYLAXIS AND IDIOSYNCRASY TO IMMUNITY 



In a previous chapter immunity was described as a relative, not absolute, 

 state subject to fluctuations; equally dependent upon intrinsic and extrinsic 

 factors. 



Susceptibility and hypersusceptibility (hypersensitiveness) are also relative 

 conditions subject to changes and dependent upon both intrinsic and extrinsic 

 factors. Furthermore, it is observed that in many instances the same factors 

 that are active in producing immunity are also active in producing allergy and 

 anaphylaxis. All the demonstrable facts relative to these conditions indicate 

 that they are chemical reactions fundamentally related. 



It is well known that living organisms in general try at times with a sur- 

 prising degree of success and again with conspicuous failure to cope with changes 

 in their environment and pabulum; of two men transferred from a balanced 

 diet to a deficient diet one will adjust himself to the change and continue to 

 enjoy good health, the other fails to and suffers scurvy or beriberi; of two patho- 

 genic bacteria invading a man under identical conditions, one fails to withstand 

 the unfavorable elements of its environment and dies, the other survives, mul- 

 tiplies and produces infection. In such cases vulnerability depends upon the 



