IXFI':CTI()X AXI) IXKl'X'TIOUS AGENTS 35 



luive also been found in the seeds of Ricinus communis, Croton 

 iif/Ihnn, and the bark and leaves of the locust tree {Robinis 

 pscudoacacia). In the animal kinodom one finds toxins in the 

 fi'landular secretions of a number of snakes, the ones most studied 

 I)eing' those of the cobra, water moccasin, copperhead, and rattle- 

 snake. Flcxner and Noguchi found the venoms of the first two 

 rich in neurotoxins but attributed the injurious effect of rattle- 

 snake venom to hemorrhagin (vascular toxin). 



It is not uncommon for a plant or animal to produce several toxins 

 that differ in their affinity for different tissues. Perhaps the 

 most common is a hemotoxin which destroys red blood cells. This 

 type of toxin is found in arachnolysin (from certain spiders), 

 ichthyotoxin (in eel serum), phrynolysine (blood and skin of 

 toads), in tlie poisojious secretions of certain fish {TnicJnyius 

 draco), and in scorpions. These toxins of plant and animal origin 

 are called ''phytotoxins" and ''zootoxins," respectively. For a 

 more comprehensive discussion of the latter, the student is referred 

 to a paper by Do Amarol (1928). 



Antitoxins. — The antitoxins are specific neutralizing substances 

 produced by the reticulo-endothclial system of the body and given 

 off into the general circulation. Normal rabbit blood will not 

 neutralize diphtheria toxin, but after the animal is given several 

 small injections of toxin, it is found tliat the blood will neutralize 

 the toxin, hence it is said that this blood contains diphtheria anti- 

 toxin. CI. tetani, CI. hotidinum, CI. ivelcMi, and a few other 

 anaerobes produce soluble toxins that show remarkable specificity. 

 Recently Dick and Dick (1924) have shown that scarlet fever 

 streptococci produce a soluble toxin responsible for the rash in 

 scarlet fever. It is possible to purchase specific antitoxins for 

 each of these bacterial toxins. 



Ptomaines." — Other toxic substances are formed in culture 

 media as the result of bacterial enzymes acting upon the food 

 material. AVhen enzymes act upon amino acids in such a way 

 as to remove the carboxyl group (COOH) the process is called 

 decarhoxylization and the residue is an amine. 



Toxic amines are called ''ptomaines." Kendall (1931) has made 

 the most extensive investigation of bacterial metabolism and has 

 noted histamine production by a variety of organisms. Ptomaines 

 are not only nonspecific but are ]iroduced by many saprophytes 

 as well as parasites. 



