POISON SUMACH, 103 
and oceasionally produces the most severe effects. 
It is however extremely various in its action, up- 
on persons of different idosyncrasies. Some can- 
not come within the atmosphere of the shrub, 
without suffering the most violent consequences. 
Others are but slightly affected by handling it, 
and some can even rub, chew, and swallow the 
leaves without the smallest inconvenience. 
The most formidable cases in persons subject 
to this poison, usually commence within twenty 
four hours after the exposure. . The interval is 
sometimes longer, but more frequently shorter. 
The symptoms are generally ushered in by a 
sense of itching and a tumefaction of the hands 
and face. The swelling gradually extends over 
yarious parts of the body, assuming an erysipela- 
tous appearance. The inflamed parts become 
more elevated, acquiring a liyid redness, attended 
with a painful burning sensation, Small vesicles 
now appear upon the surface, which extend and 
run into each other. They contain a transparent 
fluid, which by degrees becomes yellow, and at 
length assumes a purulent appearance. A dis- 
charge takes place from these vesicles or pustules, 
giving rise to a yellowish incrustation, which af- 
terwards becomes brown. In the mean time an 
insupportable sensation of itching and burning is 
