122 JOURNAL AND PROCEEDINGS. 



vegetable matter. Finally the larvae become flies and escape by 

 eating their way out. For use, these excrescences should be 

 collected when of full size, just before the eggs are hatched. All 

 parts of this plant contain a large amount of gallo-tannic acid, and 

 the bark is often used in tanning. The berries have a sour, 

 astringent taste and owe their acidity to malic acid, which, however, 

 according to Mr. Cossens, is not contained in the berries themselves 

 but in the pubescence which covers them. An infusion of the fruit 

 has been used as a refrigerant drink in fevers and as an astringent 

 gargle in ulcerated sore throat. 



Rhus Copallina^ dwarf sumach, mountain sumach, or the Gum 

 Copal tree, is a shrub with running roots, one to seven feet high, 

 inhabiting rocky hills. The only known station for it in Canada is 

 the Thousand Islands. Its branches are downy, and the petioles 

 between the leaflets are wing-margined. Gum Copal so largely used 

 in making varnishes, is the product of a number of different trees, 

 one of which, according to some authorities, is the Rhus Copallina. 

 The plant possesses similar, but less strongly marked, medicinal 

 properties to Rhus Glabra, already described, and may be used 

 as a substitute therefor. 



Rhus Typhina, staghorn sumach, grows very commonly through- 

 out Canada, from Nova Scotia to Lake Superior, along railway 

 tracks and on sterile hillsides. It forms a tree ten to thirty feet 

 high, with orange colored wood. The branches and stalks are 

 densely velvety-hairy, with serrate leaflets pale beneath. This, the 

 the fourth and last of the innoxious species to be described, also 

 possesses properties similar to Rhus Glabra, and may be substituted 

 when that plant cannot be got. 



Of the four indigenous species which have poisonous properties, 

 one is an inhabitant of the Southern States, and a second of 

 California, while the third and fourth are common in all parts of 

 North America between the 35th and 60th parallels. Since their 

 poisonous^ and probably their therapeutic, effects are similar, I will 

 first give a short description- of each species and devote the re- 

 mainder of my remarks to the physiological and therapeutic actions 

 of Rhus Toxicodendron, the common form of poison ivy in Canada. 

 Rhus Pumilum, growing only in the Southern States, and very 

 common in North Carolina, is a pubescent shrub, about a foot high, 

 said to be the most poisonous of the eastern varieties. The pinnate 



