LAKIX LARCH. 259 



Canada pitch is in opaque, reddish-brown masses, hard and brittle at 

 ordinary temperatures, but readily softening by the application of little 

 heat. It contains resin, and a minute proportion of volatile oil. 



Preparations. Of Canada turpentine : none. Of Canada pitch : Em- 

 plastrum picis Canadensis Canada pitch plaster. United States Pharmaco- 

 pveia. 



Medical Properties and Uses. Canada turpentine does not differ mate- 

 rially in action from common turpentine, and is seldom employed medici- 

 nally. Canada pitch, applied externally in the form of a plaster, produces 

 mild rubefaction, by virtue of its volatile oil. It is employed to some extent 

 as a substitute for Burgundy pitch, the product of A. excelsa of Europe. 



The bark of A. Canadensis is very astringent and is largely used in 

 tanning. An extract prepared from it occurs as a commercial article and 

 has been employed to some extent as a topical astringent. It appears to 

 have no advantages over other common vegetable astringents. 



LARIX. LARCH. 



Larix Americana Michaux. American Larch, Tamarack. 



Description. Catkins terminating short lateral branches of the preced- 

 ing year, the sterile from leafless buds, the fertile mostly with leaves below ; 

 cones ovoid, | to f inch long ; scales few, rounded, not thickened. Leaves 

 needle-shaped, soft, fasciculate, deciduous. A tall, slender tree, with hori- 

 zontal branches, and thin scaly bark, from which exudes an aromatic resin. 



Habitat. In swamps and marshy borders of small lakes and ponds from 

 New England to Pennsylvania and Wisconsin ; most common northward. 

 It attains its greatest perfection in peat swamps ; indeed, an abundant 

 growth of this tree in a swamp is almost certain evidence of a deposit of 

 peat. 



Parts Used The inner bark and the resinous exudation not official. 



Constituents. It does not appear that an analysis of the bark of the 

 American larch has yet been made. The bark of an allied European 

 species L. Europcea contains tannin of a peculiar character, and another 

 acid principle allied to pyrogallic acid and pyrocatechu. The resinous 

 exudation contains resin and a small quantity of volatile oil. 



Preparations. The bark is commonly employed in decoction. The 

 resinous exudation, is an article of commerce under the name of tamarack, 

 or spruce gum. It is prepared, generally by sophistication with other 

 cheaper substances, for use as chewing-gum. 



Medical Properties and Uses. Little is known of the therapeutic prop- 

 erties of tamarack bark, though it is said to be laxative, tonic, diuretic, 

 and alterative. Tamarack gum has no inherent medicinal properties. 

 Being chewed, it stimulates the salivary secretion, and to some dyspep- 

 tics affords a certain amount of relief ; but whether this is because of the 



