TOXINS 111 



differ from ptomains, which are cleavage products from the medium 

 upon which the bacteria have been grown. Furthermore, ptomains of 

 similar properties may be produced by several different kinds of bacteria, 

 and accordingly are non-specific in nature. Toxins, like ferments, can 

 give rise to antibodies, whereas ptomains cannot produce them. 



The extracellular or soluble toxins differ from the intracellular toxins 

 in that they are more easily diffused throughout the animal juices, and 

 that their diffusion occurs independently of the invasiveness of the 

 bacteria, so that comparatively few microorganisms growing at some 

 unimportant focus, and causing but slight local lesions, may be able to 

 give rise to profound general intoxication. This is well illustrated in 

 diphtheria, where the local lesion in the throat may be quite small, 

 and in tetanus, where it may indeed be undiscoverable yet either, 

 through the action of their toxins on special tissues, may cause profound 

 intoxication and death. 



Selective Action of Toxins. Extensive studies of the toxins of 

 diphtheria and tetanus and of cobra venom have shown that they are 

 quite complex, and are usually composed of two or more distinct and 

 separate toxins possessing different pathogenic properties, although one 

 of these may predominate in producing symptoms. 



All infections with the group of true toxin-producing bacteria mani- 

 fest certain non-specific symptoms of general intoxication, namely, 

 fever, headache, malaise, prostration, etc.; but the typical symptoms 

 of these diseases are due to the remarkable selective action of the toxins 

 upon certain cells or organs, dependent upon the ability, chemical, 

 physical, or both, of the toxin to combine with these specific cells. For 

 example, tetanus toxin contains tetanospasmin, that has a special 

 affinity for nervous tissue; and tetanolysin, a poison that has a 

 selective affinity for erythrocytes and is hemotoxic. Ehrlich has shown 

 that these are really different toxins, and not one toxin with a two-fold 

 function, even the antitoxins of the two being different. Similarly, the 

 general symptoms and necroses of diphtheria are attributed to the main 

 toxin of the bacillus, and the nerve lesions and paralyses to a secondary 

 but distinct secretory product known as toxon. This latter view of 

 Ehrlich's, however, is much disputed, many investigators believing that 

 toxon represents a degenerated or modified form of the one toxin. 



The special affinities of toxins for certain tissues have analogies 

 among the poisons of higher plant life, as, for example, strychnin has a 

 similar selective affinity and is said to be specific in its action upon the 

 motor cells. 



