THE HAMILTON ASSOCIATION. 12/ 



by Rhus is peculiarly interesting as offering a plausible solution of 

 what are generally regarded as fabulous stories of the deadly effects 

 of the upas tree of Java, under which the wearied traveller laying 

 himself down sinks into that sleep which knows no waking. Is it 

 not at least within the bounds of possibility there may be a Javanese 

 tree possessing similar, perhaps stronger, noxious properties to Rhus 

 Toxicodendron, and thus capable of poisoning its surrounding 

 atmosphere ? 



The poisonous effects of Rhus are both local and constitutional., 

 according to the idiosyncrasy of persons ; acting upon some only 

 locally, upon others only constitutionally, and upon yet another, 

 and the most frequently met class, in both these ways. A certain 

 constitutional predisposition is requisite for the occurrence of 

 poisonous symptoms, many individuals being quite insusceptible. 

 I myself am a case in point, having often rubbed both Rhus 

 Venenata and Rhus Toxicodendron, as well as their juices, over my 

 hands and face without suffering the slightest inconvenience there- 

 from. To illustrate the peculiar virulence of this plant toward some 

 constitutions, I might state that the celebrated chemist Fontana, 

 knowing himself to be easily poisoned by it, and wishing to examine 

 into its properties, caused specimens to be got ready by another 

 person, but accidently touching one of the leaves, under some 

 water into which it had dropped, in a short time began to siiffer 

 from its poisonous effects. This susceptibility varies greatly under 

 certain conditions of animal and atmospheric temperature. In 

 some persons a difference is observable whether in a warm or cold 

 climate, and some suffer only on very hot days. With others climate 

 and season seem to make very little difference. Children are much 

 more liable to be poisoned than adults, and females than males. 

 When the skin is moist the poison is more readily absorbed. A 

 gentlemen who had often handled the plant with the greatest 

 impunity, experienced his first attack through rubbing against some 

 of it while his skin was still undried after bathing, and though he 

 has several times since rubbed the plant over the dry skin, has 

 suffered no ill-effect. For this reason also, persons perspiring, 

 especially if fatigued, are more liable to be affected. 



Instances are related in which a periodical return of the 

 symptoms of poisoning, without fresh exposure, has. occurred for a 

 number of years. This is doubted by some, who ascribe the 



