OLIVE OIL 655 



the Cape, now imported in considerable quantity, are also 

 inferior to gum arabic. 



Tragaeanth is collected in Asia Minor, mostly exported 

 from Smyrna, and occurs in thin, semi-transparent, tough, 

 horny, white-grey or yellow lamellae or plates, and marked 

 with arched or concentric ridges. It is tasteless and odour- 

 less . Although readily soluble in boiling water, it is sparingly 

 soluble in cold water, which swells it into a jelly containing 

 starch, as is indicated by the iodine test. Tragaeanth con- 

 tains a neutral gum, bassorin, which, gelatin-like, swells up, 

 is not dissolved either by hot or cold water, but is soluble 

 in alcohol. 



British gum or dextrin (C 6 H 10 5 ), much used in calico 

 printing, is made by treating starch with dilute nitric acid, 

 drying and heating it to about 240 Fahr. 



ACTIONS AND USES. Gums are the least nutritive of the 

 carbo-hydrates ; when swallowed, they are dissolved by the 

 alimentary secretions, and in part converted into sugar. 

 They are occasionally prescribed for ensheathing the mucous 

 surfaces in catarrh and diarrhoea, and as demulcent injec- 

 tions in inflammation of the bowels and bladder, but for 

 veterinary purposes are usually superseded by well-boiled 

 linseed or starch gruels. For making emulsions, electuaries, 

 and boluses, gums have the disadvantage of speedily drying 

 and hardening. They are frequently used to suspend 

 powders such as the salts of bismuth, and also to form 

 emulsions with volatile and fixed oils. 



DOSES, etc. Gums may be taken almost ad libitum. 

 Horses and cattle may have ij. to giij. ; foals, calves, and 

 sheep, i. ; and dogs, grs. xx. to grs. xl. An ensheathing 

 mucilage is made with one part gum to six of water. 



OLIVE OIL 



OLEUM OLIV.E. The oil expressed from the ripe fruit of 

 Olea Europaea (B.P.). Nat. Ord. Oleaceae. 



Several varieties of the evergreen Olea Europaea grow 

 abundantly in the countries bordering the Levant and 

 Mediterranean. From the stem a resinous juice once used 



