558 EUPHORBIACEtE. 



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 M^heu 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. 



EUPHOKBIACE^. 



EUPHORBIUM. 



Euphorbiwm, Gum Euphorbium; F. Gomrae-resine d'Euphorbe; 



G. Euphorbium. 



Botanical Origin — Eiq^horbia resinifera Berg, a leafless, glaucous, 

 perennial plant resembling a cactus, and attaining G or more feet in 

 height. Its stems are ascending, fleshy and quadrangular, each side 

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

 intervals with pairs of divergent, horizontal, straight spines about I of 

 an inch long, and confluent at the base into ovate, subtriangular discs. 

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

 indicating a leaf-bud. The inflorescence is arranged at the summits of 

 the branches, on stalks each bearing three flowers, the two outer of 

 which are supported on pedicels. The fruit is tricoccous, -^ of an inch 

 wide, with each carpel slightly compressed and keeled.^ 



The plant is a native of Morocco, growing on the lower slopes of the 

 Atlas in the southern province of Suse. Dr. Hooker and his fellow- 

 travellers met with it in 1870 at Netifa and Imsfuia," south-east of the 

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



History — Euphorbium was known to the ancients. Dioscorides^ and 

 Pliny* both describe its collection on Mount Atlas in Africa, and notice 

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



1 Fig. in Bentley and Trimen's Med. the Linnean Soc. Bot. xvi. (1878) 662. 



PlanU, part 24 (1877). ^ Lib. iii. c. 86. 



- Or Mesfioua, according to Ball, who also * Lib. v. c. 1 ; lib. xxv. c. 38. 

 quotes the province Demenet. — Journ. of 



