Drugs 



343 



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On some estates, the evapora- 

 tion is effected by steam- 

 heaters. As stated above, 

 Curacoa aloes is frequently 

 described as "Barbados aloes" 

 from the fact that in the early 

 part of last century the bulk 

 of the drug from the West 

 Indies came from the British 

 island. The trade, however, 

 has almost disappeared, and at 

 the present day the drug is 

 produced on only one estate. 

 The plant cultivated is A . vera. 



The famous Socotrin aloes 

 is prepared by much cruder 

 methods. The juice is col- 

 lected in goatskins placed in 

 shallow hollows scooped out in 

 the ground, and allowed to partially evaporate in the sun. It reaches this country as a 

 pasty or even semi-fluid mass which is dried at a gentle heat before use. Cape and Natal 

 aloes is prepared in a way similar to that adopted in the West Indies. 



The appearance of the drug when it reaches the market is largely dependent upon the 

 methods employed in its preparation. When the juice is rapidly concentrated and quickly 

 cooled, the mass breaks with a glassy or vitreous fracture as in Cape and Curacoa aloes 

 (" glassy " aloes). When evaporated slowly the mass becomes dull and opaque, and is known 

 as " livery " or " hepatic " aloes, as in the case of the drug from Socotra, Zanzibar, Natal, and, 

 in some cases, from Curacoa. 



Aloes is used as a purgative, and is one of the most valuable of this class of drugs. Its 

 action is due to the presence of the crystalline, bitter principle aloin. 



■* : il3<&% * 



Photo by W. G. Freeman, Esq. 



ALOES 



GUMS AND RESINS 



BALSAMS, BALSAMIC RESINS, AND GUM-RESINS 



These products are usually of little commercial importance, and they are almost wholly 

 used in medicine. The most important of the balsams and balsamic resins are storax, 

 benzoin, the balsams of Tolu and Peru, and Dragon's blood (obtained from the fruits of a 

 rattan palm {Calamus draco) growing in Sumatra and Borneo, and used chiefly as a red stain 

 for spirit varnishes. The best known gum-resins are myrrh, olibanum or frankincense, 

 galbanum, asafcetida, and ammoniacum. Many drugs are used for the sake of the resins 

 they contain, these not being exuded by the plant but secreted in roots, leaves, etc., from 

 which they must be extracted by chemical processes. 



GUMS 



The term gum is loosely applied in commerce to a number of different products, which are 

 better classified into the following groups : — 1. True gums, such as Acacia gum, Tragacanth 

 gum, etc. 2. Varnish resins, such as "Gum dammar," " gum copal," etc. 3. Balsamic 

 resins, such as "Gum benjamin or benzoin," etc. 4. 'Gum-resin's, mixtures of gum and 

 resin, such as " gum myrrh," "gum asafcetida," etc. 5. Dried 4 -plant juices, such as " Gum 

 opium " and " gum kino." 



