MacDougal: POISONOUS influence of cypripedium. 35 



irritating to him as Rhus toxicodendron. *********** 

 Other but more indefinite reports sustain the character of this plant." 



Prof. H. G. Jesup reviews the statements, brought together 

 in the Bulletin of the Torrey Club, and offers the following cir- 

 cumstantial evidence on the subject.''' 



"A lady near whose home grew a fine clump of Cypripedium spectabile 

 had been in the habit of gathering it when in bloom. * * * At such 

 times for four or five successive seasons she suffered from symptoms of 

 Rhus poisoning, but on careful examination no Rhus could be found where 

 the Cypripedium grew. These symptoms invariably appeared whenever the 

 Cypnpedium was in the house and disappeared with its removal, and on 

 her removal to another part of the country never reappeared. In fact, 

 when she ceased collecting the plant she escaped entirely. 



* * * * One of my own students had been in the habit of handling 

 Rhus with impunity, and had done so for years. Not long since he was 

 severely poisoned immediately after having gathered and handled a large 

 quantity of C. spectabile, and, in view of the above facts, very naturally 

 attributes his trouble to this plant." 



The latter article was brought to the author's attention when 

 he and other niembers of the botanical staff of the University 

 of Minnesota were themselves objects in circumstantial evi- 

 dence, and it was determined to secure some positive evidence 

 on the matter. The author, while in the field at Twin lakes, 

 near Minneapolis, September 7th, 1893, met with several well 

 grown plants of C spectabile, with newly formed seed pods. A 

 robust specimen was broken off near the base of the stem, and 

 the leaves were brushed lightly across the biceps muscle of the 

 bared left arm. A slight tingling sensation was felt at the 

 time, and fourteen hours later the arm was greatly swollen 

 from the shoulder to the finger tips. The portion touched by 

 the plant — covering an area of 50 sq. cm. — was violently in- 

 flamed and covered with macules, accompanied by the usual 

 symptoms of dermatitis, and constitutional disturbances. By 

 treatment of the most approved kind the arm was reduced to 

 its normal size in ten days, but the effects were perceptible a 

 month later. The severity of the test has prevented its repeti- 

 tion. The facts obtained are certainly conclusive as to the 

 poisonous qualities of this plant. They are, at least so far as 

 the author is concerned, wlio would have been satisfied with a 

 much less pronounced result. 



An examination of the two species reveals the presence of 

 two forms of hairs in great abundance. {See Plate III.) 



One is a curved-pointed septate hair, the apical cell of which 

 has hard, brittle walls, and is easily detachable from the basal 



7. Botanical Gazette. 18:142. April, 1893. 



