806 



MANUAL OF POISONOUS PLANTS 



ANONACEAE 



APOCYNACEAE 



placed on the arm for fifteen minutes. When in contact with the air it produces the 

 characteristic non toxic varnish. The resinous products from the latex of the Rhus give 

 black compounds with the alkali hydroxides. The irritating properties he thinks will be 

 found to be connected with the presence or the relations of these hydroxyl groups. 



This writer found that the milk sap of Rhus vernix is analagous in almost every 

 particular to the Japanese lac. Warren agrees with nearly everyone else that the bacterial 

 infection theory has very little to support it. Nor is there much to support the recently 

 elaborated theory of immunity. He shows how a popular impression in regard to supposed 

 immunity has become widespread even among scientists. It has not, however, been demon- 

 strated. In the same way, contrary to the early published records, Rhus Michauxii has 

 been shown by Warren and Trelease not to be poisonous. As to treatments, Warren, after 

 an extensive investigation of the subject, states that the great majority are empirical. 

 "There is no specific for this troublesome complaint. Remedies which have alleviated 

 the symptoms in one case have proved utterly valueless or worse in others." The follow- 

 ing species are listed by Warren as poisonous: 



Rhus venenata D. C. (R. vernix L.) ; Rhus radicans L,.; Rhus Toxicodendron I/.; 

 Rhus diversiloba Torr. & Gray; Rhus Rydbergii Small; Rhus Metopium L,. ; Rhus flori- 

 dana Mearns: Rhus littoralis Mearns; Rhus vernicifera DC; Rhus succedanea I/.; Rhus '< 

 sylvestris Sieb. & Zucc. ; Rhus Wallichii Hook, fils; Rhus Griffithii Hook, fils; Rhus striata 

 R. & Pav. ; Rhus perniciosa H. B. & K. ; Rhus chinensis Mill.; Rhus javanica L,.; Rhus 

 caustica Hook. & Arn. ; Rhus lucida L,. 



