ANACARDIACEAE RHUS 



611 



of development." There were also large excoriations from which fluid was 

 exuding freely, which on drying formed small crusts. The hands were also 

 covered. "The subjective symptoms were great retching and burning of the 

 parts affected, with the feeling of local discomfort, consequent upon so great 

 swelling of the features. The eyes were nearly closed. There was a slight 

 general febrile action." Dr. White also reports the death of a child from a 

 severe case of poisoning from poison ivy. The child though healthy was not 

 robust. A recent case was reported from Packwood, Iowa, where a fourteen- 

 year-old girl died after terrible suffering from the effects of coming in con- 

 tact with the ivy ; her face alone showing the eruption from the poison. 



Hundreds of persons are poisoned every year from the three species. 

 Dr. White says : 



Fig. 344. Poison oak (Rhits diversiloba), 

 showing leaves, flowers, and fruit, one-third 

 natural size. (Chesnut, U. S. Dept. Agr.) 



Taking the simple vesicle, with scarcely any erythema surrounding it or any very per- 

 ceptible infiltration of the underlying tissues, as the type of the eruption, whether occurring 

 singly or in groups, we may have in a small percentage an abortive attempt at vesiculation, 

 and an arrest of the development at the papular stage a failure, that is, of the free exudation 

 to force apart the layers of epithelial cells; or a considerable infiltration into the papillary 

 layer may elevate a cluster of the vesicles noticeably above the general surface, or they may 

 be surrounded by a well-defined erythema or congestion of the tissue immediately surrounding 

 them, in consequence mainly of the scratching and itching, which are the only subjective 

 symptoms present. 



In the severe cases, we have greater areas of simple erythema, a multiplication of the 

 number of vesicles either single or massed in close contiguity, and covering large surfaces, 

 or by fusion forming blebs a greater infiltration into the underlying corium, with propor- 

 tionate distension of the capillaries and external redness, and a free exudation of serutn into 



