28 PRODUCTS OF BACTERIAL ENERGY 



than the extracellular poisons. They are probably quite complex 

 in activity as they give rise to various anti-poisons when in the 

 animal body. These poisons are resistant to heating at 8oC. and 

 keep under artifical conditions much longer than soluble toxins. 



The toxic bacterial proteins are best exemplified by tuberculin. 

 This is complex mixture of the proximal principles of the tubercle 

 bacillus and is probably albuminose in character. These sub- 

 stances are almost as specific for their own germs as the toxins and 

 much more so than the endotoxins. They are capable of produc- 

 ing a reaction in animals similar to that which might be produced 

 by the organisms themselves. For example tuberculin, wholly 

 free from tubercle bacilli, will produce a reddening of the skin or a 

 rise of temperature if injected into a tuberculous individual. The 

 dead tubercle bacillary mass if placed beneath the skin of a healthy 

 guinea pig will set up a local limited miliary tubercle. The 

 reactions from mallein and luetin (q.v.) injection are due to toxic 

 proteins. The proteins are usually thermostable, that is not 

 destroyed at iooC.; this is also called coctostabile. 



In practice it may not be so simple to separate bacteria that 

 produce the various poisonous elements as the above descriptions 

 would indicate. Toxins are all in a sense specific, that is they 

 are for the most part selective in action, and are harmless if 

 swallowed. The diphtheria toxin is absorbed from a raw inflamed 

 surface under cover of an exudate composed of fibrin and bacteria. 

 The tetanus toxin is absorbed from its seal of manufacture in the 

 depths of a punctured wound. The endotoxin of typhoid bacilli 

 has no pathogenic effect if swallowed or rubbed in skin or mucous 

 membrane. If it be injected under the skin in the absence of 

 bacteria it will call forth reactions on the part of the body similar 

 to those expressed when living typhoid germs are circulating. 

 Toxins are again relative in their affinities. Tetanus toxin is fatal 

 for man and horses while rats and birds are resistant to it. We 

 use this expression of specificity for determining the nature of 

 certain germs. We may speak of failures to react as failures 



