(Ivy, . Oak, . and. Sumac. Poisoning). By JOHN L. WOBDEN, (New York) As a aequel to the excellent articles that recently have appeared In ... It does not spread beyond the area of contact except by scratching, rubbing, movement of clothing, or other mechanical means. ... PROPHYLAXIS AND TREATMENT Persons of known susceptibility to Rhus Poisoning should make it a point to learn how to recognizeanbsp;...