FACTS REGARDING BACTERIAL TOXINS 191 



ferrecl to simply as the toxins. These toxins differ in their 

 ell'i.'ctN from the intracellular poisons in that s^cific actions on 

 certain ti-> :i--s are often manifested. Thus the toxins of the 

 diphtheria, the tetanus, and the botulismus bacilli all act on 

 the ner\o i- system ; with some of the pyogenic bacteria, on the 

 other haiul, poisons, probably of similar nature, produce solution 

 of red blood corpuscles (this last might be thought to explain 

 the aiuemias so common in. the associated diseases, but it is to 

 be noted that, in cultures at least, these htemolytic toxins are 

 developed in very small amounts). In the action of many of 

 these toxins the occurrence of a period of incubation between 

 the introduction of the poison into the animal tissues and the 

 appearance of symptoms is often a feature. 



The whole question of the parts played by toxins in bacterial 

 action is manifestly very complex. On the one hand, we have 

 a few processes, for example, diphtheria and tetanus, in which 

 UTV characteristic effects are produced on special tissues, these 

 being accounted for by the formation of soluble toxins which 

 are capable of being separated from the bacterial growths in vitro. 

 On the other hand, we have the great mass of bacterial infec- 

 tions. With regard to these, the distribution of the bacteria 

 in the bodies of infected animals makes it necessary for us 

 to take for granted that a toxic action is at work. All that 

 we know, however, regarding a possible explanation of such 

 toxicity is that the bodies of the bacteria or substances directly 

 derived from them are capable of producing pathogenic effects. 

 These effects are of a non-specific character in the sense that 

 they are not the result of an action on any particular tissue in 

 the body, but on the vital processes of the organism as a whole. 

 We are at present entirely ignorant of the interpretation to be 

 put, for instance, on the lowering of bodily temperature on the 

 one hand and of the occurrence of fever on the other, both of 

 which may be produced by the injection of the so-called intra- 

 cellular toxins in varying doses, and we are ignorant of the 

 relations which either event may have to the bringing into play 

 of the defensive mechanisms of the body. At the same time we 

 must admit the possibility that with any one species of organism 

 different effects may be produced by, it may be, different elements 

 in the protoplasm of the invading bacterial cell. Some of these 

 elements may act on certain groups of specialised cells of the 

 body, such as those of the nervous system, liver, or kidneys, 

 giving rise to what we are forced to describe in general terms as 

 disturbances of metabolism. Other poisonous elements may 

 mainly act on the defensive cells of the body, of which the 



