POISONING BY PLANTS. GENERAL PRINCIPLES 19 



NH 2 , and cholin, muscarin,neurin which are much more complex. These 

 substances are formed in decomposing flesh. Cholin and muscarin are 

 found in the toad-stool, Amanita muscaria. Muscarin and neurin are both 

 very poisonous, whereas cholin is slightly toxic. 



Cholin is found in the seeds and fruits of Pinus cembra, nut of Areca- 

 catechu, endosperm of coconut (Cocos nucifera) root of sweet flag Acorus- 

 calamus, hop Humulus lupulus. Betain another member of the group 

 occurs in the juice of the beet and in the tuber of Helianthus tuberosus. 

 All these substances are strong bases and answer the general reactions for 

 alkaloids. Immune substances are not produced for these chemical poi- 

 sons as for the phytotoxins later described. 



Glucosides. These are chemical substances of considerable complexity 

 and yield glucose on decomposition with one or more other compounds, 

 usually of an aromatic nature. The reaction is mostly hydrolysis. For 

 example, amygdalin is hydrolyzed by emulsin, an enzyme, to glucose, 

 benzaldehyde and prussic acid. 



C 20 H 27 , NOn + 2H 2 = 2C 6 H I2 6 + C 6 H 5 CHO + HCN. 



This reaction expresses that of the cyanogenetic glucosides or those 

 which on hydrolysis yield hydrocyanic, or prussic acid, a deadly poison. 



Loew from the chemical standpoint states that all substances which 

 are capable of acting on aldehyde or amino groups, even when in dilute 

 solution, must be poisonous for living tissue on which they will exert a 

 substituting action. The greater the reactivity of a substance for alde- 

 hyde (CHO) or amino (NH 2 ) groups, the greater will be its physiologic 

 effect and its toxicity. 



Vegetable Toxins (Phytotoxins). The production of substances 

 possessing the essential features of the toxins is not limited entirely to 

 the bacterial cell. They are found in the flowering plants and are called 

 phytotoxins. The chief phytotoxins are abrin from the Job's tear plant 

 Abrus precatorius; crotin from the seeds of Croton tiglium; ricin from the 

 castor-oil bean, Ritinus communis; robin from the leaves and bark of 

 the black locust, Robinia pseudacacia; phallin from the toad-stool A manita 

 phalloides, and the toxin causing hay-fever found in pollen grains. These 

 substances are very similar, resembling proteins in many respects, for 

 they can be salted out of solutions in definite portions of the precipitate, 

 are precipitated by alcohol and are slowly destroyed by proteolytic 

 enzymes. Recent work by Harris, Mendel and Osborne has shown 



