120 INFECTION 



The most important plant toxins (phytotoxins) are ricin, abrin, 

 crotin, and pollen. All possess more or less toxic qualities; the first 

 three either agglutinate or hemolyze the corpuscles of certain animals. 

 Antitoxic serums have been prepared that will neutralize the respective 

 toxins, and this factor constitutes the most important evidence of their 

 toxin-like character. 



General Properties. These toxins resemble proteins in many re- 

 spects. Jacoby, however, has placed them in the same class as bacterial 

 toxins and enzymes, i. e., large molecular colloids closely resembling the 

 proteins, but still not giving the usual protein reaction. More recent 

 work by Osborne, Mendel, and Harris, 1 however, does not support 

 Jacoby's view. These observers found the toxic properties of ricin 

 inseparably associated with the coagulable albumin, and were able to 

 isolate it in such strength that 10 1 00 milligram was fatal per kilo of rabbit, 

 and solutions of 0.001 per cent, would agglutinate red corpuscles. 



Relation to Immunity. The phytotoxins, since they obey the same 

 laws as bacterial toxins, have been very serviceable in the study of im- 

 munity; they are more stable than the latter, and can be handled in 

 more exact and definite quantities. They have apparently the same 

 haptophore and toxophore structure as bacterial toxins; antitoxins are 

 readily produced by immunizing animals, and seem to be specific for the 

 toxins; in fact, Ehrlich made his earliest observations on the specificity 

 and quantitative factors in toxin-antitoxin immunity from a study of 

 these plant toxins. 



The Toxin of Hay-fever. Pollen toxin has been described by 

 Dunbar 2 as the etiologic factor in the production of hay-fever. In all, 

 the pollen of 25 varieties of grass and seven varieties of plants have been 

 found capable of producing attacks of hay-fever in susceptible persons. 

 This susceptibility to pollen intoxication is, fortunately, limited, and the 

 sudden onset of an attack and the characteristic symptoms indicate an 

 anaphylactic reaction due to sensitization with pollen protein. Dunbar 

 has succeeded in producing a pollen antitoxin, which will be described 

 in the chapter on Passive Immunization; the reports of various 

 observers are, however, at variance in regard to its therapeutic value. 



It is highty probable that the toxic substance in ivy, sumac and 

 other plants responsible for vario.us forms of dermatitis venenata, is of 

 the nature of plant or phytotoxin of protein nature. 



1 Amer Jour. Physiol., 1905, 14, 259. 



2 For full review of this subject see Glegg: Jour. Hygiene, 1904, 4; Liefman: 

 Zeit. f. Hygiene, 1904, 47, 153; Wolff-Eisner, Deut. med. Woch., 1906, 32, 138. 



