RHUS. • 139 



stitutions in very different degrees. While some are affected 

 with a cutaneous eruption by their exhalation at the distance of 

 twenty feet, others are not affected by freely handling them, or 

 by applying their juice to the larynx and fauces. 



€€ The following circumstances have considerable influence in 

 varying in the same person the aptitude to the reception of 

 poison : 



" First. A warm or cold climate ; in southern, more active than 

 northern. Second. Different seasons of the year. The Rhus 

 vernix never affects me in the smallest degree, except on very 

 hot days in summer. TJiird. Infancy or manhood ; children 

 more readily poisoned than adults. Fourth. Exposure before 

 or after a meal. \ The plants more readily poison immediately 

 after than before a full meal 9 (Dr. Barton). Fifth. The pre- 

 sence of moisture. Country people generally believe that the 

 effluvia of plants when combined with moisture are most apt to 

 produce the eruption. Several facts induce me to think this 

 deserves credit* Sixth. A state of increased perspiration at 

 the time of exposure has a most powerful influence in favouring 

 the eruption. Of this I have had several proofs : in collecting 

 the juice of R. vernix, if in a state of high perspiration, I never 

 failed to be affected more or less with the eruption; if my skin 

 was perfectly dry, it had not the least effect upon me. Pro- 

 fessor Kalm also remarked on the R. vernix, ' I found, how- 

 ever, that it could not exert its power on me when I was not 

 perspiring.' Females, Dr. Barton says, are more easily affected 



than males." 



Dr. J. Cooper inoculated himself with some of the juice of 

 the Rhus toxicodendron. The next morning the eyelids 

 itched, and were redder than usual; in the afternoon the face 



# " 



That moisture does not destroy their poisonous qualities appears by the 



tmin 



following quotation from Fontana on Poisons. Fontana, in order to ei 

 use of the leaves of the toxicodendron, as he knew that he was easily poisoned, 

 observes, c I caused them to be got ready by another person, but I touched a few 

 of the leaves when under ivater. In four days my face and eyes swelled/ etc." 



