THE HAMILTON ASSOCIATION. 1 29 



site. This parasite lives in millions on the ' poisonous ' tree or plant, 

 but when the leaf or stalk where they cluster is touched by one's 

 hand or wrist, a score or more of them may be found clinging to the 

 skin. They cannot be seen with the naked eye, but they may be 

 removed by the edge of a sharp instrument and put on the slide of 

 a microscope. They are rather oval in shape, and have a wonder- 

 ful power of reproduction. Suppose a child touches a leaf or stem 

 with his hand or wrist, five or six of these parasites get upon the 

 iskin, huddling close together, and remaining in the same spot for 

 hours. The child doesn't feel them and can't see them, but the pests 

 at once begin to burrow under the skin, feeding and building nests. 

 In a short space of time they have increased a thousandfold, after 

 which they all move about, making little settlements all over the 

 the body, turning the skin rough and red, and producing a torment 

 of itching. These parasites are communicated even by shaking 

 hands, though the bacillus (which it really is) will not burrow so 

 readily in the skin of an adult as in the softer skin of a child. I 

 have known about eighty per cent, of a school, consisting of nearly 

 sixty pupils, to be contaminated by one small boy who had the rash 

 of poison ivy on his wrist. He was the only one in the school who 

 had been in the woods, and he had brushed through a clump of 

 poison ivy. It was the belief down to a very late period that the 

 poison from these plants was an acid or sharp juice, which, getting 

 upon the skin, irritated the part and set up an inflammation. The 

 modern microscopists know it is a parasite which can live on the 

 petals or stems of the plants named, or on human blood, and thrives 

 best on the latter. The two poison sumachs are provided with a 

 thick, viscid juice, which exudes when a branch, stem or leaf is 

 crushed or broken. In this matter are myriads of the parasites, but, 

 as already stated, they are communicated to the skin by the brief 

 contact of any exposed portion of the hands, arms, face, or any other 

 part of the body." 



On reading this strange statement I at once communicated with 

 Dr. Van Harlingen, of Philadelphia, one of our best authorities on 

 skin diseases, who told me, as I had surmised he would, that the 

 statement was a mere newspaper " yarn," which advanced an utterly 

 untenable statement, and one of which he had never even heard. 



The symptoms of rhus poisoning are violent itching, redness, 

 burning, and erysipelatous swelling of the parts subjected to its in- 



