558 EUPHORBIAOE^. 



to be 70 to 100 mkm. long, and to contain colourless masses of mucilage, 

 distinctly showing a series of layers. Crystals of calcium oxalate, as 

 well as small starch grains, are very plentiful throughout the surround- 

 ing parenchyme. 



Chemical Composition — The most interesting constituent of the 

 bark is mucilage, which is imparted to either cold or hot water, but 

 does not form a true solution. The bark moistened with 20 parts of 

 water swells considerably, and becomes enveloped by a thick neutral 

 mucilage, which is not altered either by iodine or perchloride of iron. 

 This mucilage when diluted, even with a triple volume of water, will 

 yield only a few drops when thrown on a paper filter. The liquid which 

 drains out is precipitable by neutral acetate of lead. By addition of 

 absolute alcohol, the concentrated mucilage is not rendered turbid, but 

 forms a colourless transparent fluid deposit. 



Adulteration— Farinaceous substances admixed to the powdered 

 drug may be detected by means of the microscope. 



Uses— Slippery Elm Bark is a demulcent like althsea or linseed. 

 The powder is much used in America for making poultices; it is said 

 to preserve lard from rancidity, if the latter is melted with it and kept 

 in contact for a short time. 



EUPHORBIACEJE. 



EUPHORBIUM. 



Euphorhium, Gum Euphoi-hiuin ; F. Gomme-resiiie d! Eiij>ltorhe ', 



G. Euphorhium. 



Botanical Origin— ^i/.^^/^or^m resinifera Berg, a leafless, glaucous, 

 perennial plant resembling a cactus, and attaining G or more lee 

 height. Its stems are ascending, fleshy and quadrangular, e«cli sia 

 measuring about an inch. The angles of the stem are furnished a^ 

 intervals with pairs of divergent, horizontal, straight spmcs ^"""^.^ 

 an inch long, and confluent at the base into ovate, subtriangular cus^^- 

 These spines represent stipules: above each pair of them is a depiess , 

 indicating a leaf-bud. The inflorescence is arranged at the summit ^^ 

 the branches, on stalks each bearing three flo^yers, the ^^'*^„ i^^^l^ 

 which are supported on pedicels. The fruit is tricoccous, fV ^* ^^ 

 wide, with each carpel slightly compressed and keeled.^ „ .^^ 



The plant is a native of Morocco, growing on the lower sloF« ^' ^^_ 

 Atlas in the southern province of Suse. i)r. Hooker and his leu 

 travellers met with it in 1870 at Netifa and Imsfuia,' south-east oi 

 city of Morocco, which appears to be its westward limit. ^ ^ 



History— Euphorhium was known to the ancients. Dioscori ^^ .^^ 

 Pliny* both describe its collection on Mount Atlas in Africa, '"^^ ' j^^j 

 its extreme acridity. According to the latter writer, the drug r 



1 Fig. in Bentley and Trimen's Mul. the Llnneaii Soc. Bot. xvi. (1878) 6 - 

 PlanLs part 24 (1877). ^ Ljb, iii. c. 8G. ^ 



2 Or Mesfioua, according to Ball, wlio also * Lib. v. c. 1 ; lib. xxv. c. 6s. 

 quotes the province Demenet. —/oj/rn. of 



