APEn. 24, 1908] 



SCIENCE 



655 



nized to the two poisons in the Amanita, 

 the hemolysin and the toxin. Immuniza- 

 tion with the hemolysin proceeds without 

 difficulty, the animals reacting well and 

 retaining their weight. Their serum is 

 always powerfully anti-hemolytie, a 

 strength of 1/1,000 being found after four 

 or five injections. Active immunity with 

 the toxin can also be produced, the animals 

 resisting the inoculation of two or three 

 fatal doses and their serum conferring 

 passive immunity upon other animals up 

 to a limited point. At no time, however, 

 have we obtained a higher degree of either 

 active or passive immunity with this por- 

 tion of the fungus than with the "whole 

 extracts." We are thus confronted with 

 the paradoxical condition that the glucoside 

 in the fungus for which on theoretical 

 gi'ounds an anti-body would be supposed to 

 be impossible will readily stimulate animals 

 to the production of an anti-hemolytie 

 serum, while the non-glucosidal substance 

 is thus far the barrier to the production of 

 a high degree of immunity. To just such 

 an extent as the hemolysin acts in man 

 can we obtain an efficient antitoxin, but 

 since the toxin is apparently more potent 

 in this respect than the hemolysin, no prac- 

 tical results can possibly be hoped for until 

 some method of obtaining a stronger serum 

 for this fraction of the fungus can be 

 devised. 



Finally, it has seemed to Dr. Abel and 

 myself, in view of the direct contradiction 

 which our results bear to those of Kobert, 

 an important matter to repeat some of our 

 earlier observations, and -we have confirmed 

 the conclusions as to the non-proteid char- 

 acter of the hemolysin in Amanita phal- 

 loides by obtaining proteid-free hemo- 

 lysins from other specimens of this fungus 

 from New York State and from Massa- 

 chusetts, thus covering in these studies 

 three widely separated localities. The 



hemolysins in the fungi from these three 

 different sources can all be completely 

 neutralized by the serum made by Dr. 

 Kinyoun from the Maryland fungi, a fact 

 Avhich further points to the identity of this 

 substance in various examples of the plant, 

 and its wide distribution. Indeed, no 

 typical specimens of Amanita phalloides 

 have thus far been studied in which the 

 Amanita-toxin, when present, was not ac- 

 companied by this blood-laking principle. 



Having thus shown that an anti-hemo- 

 lysin can be made for a hemolytic gluco- 

 side, it became imperative to determine 

 whether this was a fortuitous circumstance, 

 dependent upon some peculiar composition 

 of the substance employed, or whether 

 there were not other poisonous glucosides 

 with which animals could be successfully 

 immunized. 



The most important poison available for 

 these studies was the active principle of 

 Rhus toxicodendron, or poison ivy, from 

 both the theoretical and practical stand- 

 point. It had some years previously been 

 shown by Pfaff" that the poison of this 

 plant was a non- volatile oil, decomposed 

 by heat, soluble in alcohol, ether, benzine, 

 chloroform, etc., but insoluble in water. 

 The name Toxicodendrol was given to this 

 oil. Subsequently Syme^^ has concluded, 

 on the basis of extensive experimental 

 work, that the irritating substance of 

 poison ivy is a glucoside, a compound of 

 rhamnose, gallic acid and fisetin. To this 

 substance the name Toxicodendrin is ap- 

 plied. 



It is possible to obtain this active prin- 

 ciple in the fluid extract of Ehus toxico- 

 dendron, an alcoholic extract of the fresh 

 leaves of the plant, from which a tincture 



" Pfaff, Journal of Experimental Medicine, 

 1897, Vol. 2, p. 181. 



" Syme, " Some Constituents of the Poison Ivy 

 Plant (Rhus toxicodendron)," Johns Hopkins 

 University Dissertation, Baltimore, 1906. 



