BIOLOGY OF SPECIALIZED GROUPS 



surrounding media. These substances are called soluble toxins 

 or toxins. There are very few bacteria which have the power 

 of producing these toxins. Bact. diphtheriae, B. tetani, 

 Ps. pyocyanea, and B. botulinus are practically the only 

 bacteria which produce toxins of this character, with the pos- 

 sible exception of some species which produce toxin-like he- 

 molytic products. These substances are referred to below. 



Certain animals, such as snakes, eels, lizards, scorpions, etc., 

 by activity of a particular group of gland cells produce soluble 

 toxins, venoms, etc. Immunization with these animal toxins 

 produces antibodies. In some toxins, as, for example, tetanus 

 toxin, two distinct toxins can be separated tetanospasmin, 

 which has an affinity for nerve tissue, and tetanolysin (hemo- 

 lysin), which destroys the red blood cells. In diphtheria, in all 

 probability, there are also two toxins generated the princi- 

 pal toxin, to which most of the diphtheritic infection is due, and 

 another toxic substance, which is formed slowly by the bac- 

 teria and called by Ehrlich a toxon. The paralysis noted late 

 in some cases of diphtheria is ascribed to these toxons. 



The chemical constitution of toxins is unknown. A great 

 amount of research work has been done and is being done at 

 the present time along this line. Toxins are very labile sub- 

 stances and are easily destroyed by comparatively low moist 

 heat, light, chemicals, and by oxygen, even in the amount found 

 in the air. All oxidizing agents, including the enzymes of the 

 body and of bacteria, destroy toxins. They are not affected 

 by chloroform, toluol, phenol, etc., and are precipitated by 



