AFFINITIES OF TOXINS. 113 



In the case of some of the toxins (as of diphtheria 

 and tetanus) a certain time for the manifestation 

 of a toxic effect is required, even when they are 

 placed in direct contact with the cells for which 

 they have a specific affinity. As stated, the role of 

 anaphylaxis is uncertain. 



Leaving out of consideration the few instances Factors in 

 in which preformed toxins are ingested and 

 absorbed (as in botulism), the production of dis- 

 ease in a susceptible host would seem to depend on 

 two factors : First, presence in the micro-organism, 

 or secretion by it, of a toxin which is able to cause 

 a direct injury of the tissues of the host; and sec- 

 ond, ability of the micro-organism to remain alive 

 and to proliferate in the body of the host. 



Different toxins vary greatly in the cells which Direct 

 they attack. Some destroy the red blood cells to a 

 marked degree (staphylococcus and streptococcus) ; 

 others have a special affinity for the nervous tissue 

 (tetanus, diphtheria, botulism) ; some attack .par- 

 ticularly the endothelium of the vessels, causing 

 many minute hemorrhages (some of the eruptive 

 fevers, rattlesnake venom). In many other in- 

 stances the toxins have a wider range of action, 

 and many different tissues suffer to a greater or 

 less degree. Areas of necrosis in the lymphoid and 

 parenchymatous organs, and granular and fatty 

 degeneration of the latter, and of the muscles, 

 including the heart, are well known in different 

 diseases. The albumin and casts which appear in 

 the urine in various acute febrile diseases are a 

 result of a toxic action on the epithelium and endo- 

 thelium of the kidneys. 



In addition to destroying life by their direct 

 action on the cells, pathogenic micro-organisms 



