254 PHARMACEUTICAL BACTERIOLOGY 



exudate from this guinea pig is sterilized and injected into a second 

 guinea pig, together with some tubercle bacilli of the kind used in the 

 first animal, the second animal will succumb much more rapidly than the 

 first, usually within twenty-four hours. If the sterilized exudate alone 

 is injected, nothing will happen; and if the tubercle bacilli alone are 

 injected the tuberculosis will develop within a few weeks, as in the first 

 animal. It is assumed that the peritoneal exudate contains a substance 

 formed by the tubercle bacilli which has the power of greatly increasing 

 the virulency and this substance has been called aggressin. Heating the 

 exudate to 6oC. causes a further increase in the virulency of the aggressin, 

 and it was found that small amounts of the exudate were relatively more 

 virulent than larger amounts, and Bail assumes that there are two sub- 

 stances in the exudate, one which is thermolabile preventing rapid death, 

 the other thermostabile, favoring rapid death. It is assumed that a 

 bacterolysin is formed, which acting on the bacilli, liberates the endotoxin 

 which paralyzes the polynuclear leucocytes, the mononuclear phagocy- 

 tosis being undiminished. 



i. Anaphylactic Reactions. Anaphylaxis is the opposite of prophy- 

 laxis. It indicates a state of susceptibility or rather hypersusceptibility 

 to certain substances when brought in biological contact with living 

 cells. The term was originally used to indicate a condition of hyper- 

 susceptibility to diseases generally. More recently the term anaphylaxis 

 or anaphylactic shock, has been very largely applied to the hypersus- 

 ceptibility toward horse serum. The investigations into anaphylaxis 

 were prompted by the comparatively common cases of serum sickness 

 (rash, urticarias, enteritis, etc.) and the comparatively rare sudden col- 

 lapse and death, following the use of diphtheria antitoxin. These classic 

 investigations proved that the anaphylactic reaction, or state, depended 

 upon the following essentials: 



First. Injecting into the experimental animal (as rabbit or guinea 

 pig) a dose of some non-toxic protein, which sensitizes the animal specifi- 

 cally to this particular substance. 



Second. An incubation period of from eight to fourteen days, followed 

 by 



Third. A second injection of the same protein, at the close of the 

 incubation period. The anaphylactic reaction appeared almost im- 

 mediately (collapse and death). 



Fourth. The sensitization developed by the initial dose may endure 

 for months and even for years, in fact may endure for life and may be 

 transmitted to the offspring. 



The experiments also proved that the anaphylactic condition can 

 be developed toward a great variety of substances, animal, vegetable and 



