63 



3. The following species are definitely contact poisons, arranged in 

 order of their virnleuce. 



Rhus Vernix L. 



Rhus radicans. 



Euphorbia corollata. 



Cypripedium hirsutum. 



Anthemis Cotula. 



Leptilon Canadeuse. 



Clematis Yirginiana. 



Bidens frondosa. 



The nettles are not included in this list on account of the ephemeral 

 character of the irritation they produce, nor are there included a number 

 of forms which poison under unusual conditions, such as grinding or long 

 continued applications. 



4. Of the plants named, the two species of the genus Rhus are the 

 only ones affecting all upon whom experiments were tried, if we except 

 the nettles. 



5. Sixteen plants included in the list proved absolutely harmless under 

 the conditions of the experiments. Probably aU in the list with the ex- 

 ception of the first three or four may be safely handled under ordinary 

 conditions. 



The data bearing upon conclusion 3 may be tabulated as follows: 



