CHARCOAL 351 



pharmacy, sugar-refining, and other arts. One volume of 

 good boxwood charcoal absorbs into its pores 100 volumes 

 of ammonia gas, 50 of hydrogen sulphide, and 10 of oxygen. 

 The oxygen thus retained decomposes and deodorises noxi- 

 ous gases which come into contact with the charcoal. Air 

 laden with sewer gases is purified by passing it over charcoal. 

 Brown sugar in solution filtered through animal charcoal is 

 deprived of colouring matter ; crude spirit is robbed of its 

 fusel oil ; foul water is cleansed of organic impurities. 

 Urine heated with it parts with colouring matters, urea, and 

 uric acid, but not with any sugar it may contain. Vegetable 

 acids, alkaloids, and their salts are sometimes purified by 

 charcoal ; but for these pharmaceutic purposes it has the 

 disadvantage of retaining, not only colouring particles, but 

 portions of the drugs a property, however, which renders 

 it serviceable as an antidote in poisoning with opium, aconite, 

 strychnine, and even prussic acid. The charcoal mechani- 

 cally envelops and holds the poisonous particles ; half an 

 ounce, swallowed immediately after a grain of morphine or 

 strychnine, is stated to prevent absorption. 



Sprinkled over meat or game, or placed in barrels of water 

 intended for long keeping, it retards putrefaction. Unlike 

 chlorides of mercury and zinc, or other powerful antiseptics, 

 it does not, however, attack or destroy organised germs. 

 Whilst passing through the alimentary canal, it checks 

 fermentative changes, lessens acridity and fee tor of the 

 faeces ; probably also removes mucus, and exerts some de- 

 gree of healthy stimulation. As an absorbent and deodoriser, 

 it is occasionally used as a poultice, and is often sprinkled 

 over suppurating or foul wounds. Equal parts of charcoal, 

 gum arabic, and resin constitute a useful haemostatic. 



DOSES, etc. For the horse, ^iv. to i. ; for cattle, i. ; 

 for sheep and pigs, ^i. to 3 u 'j. 5 an( l f r dogs, gr. x. to grs. 

 Ix. It is usually given suspended in gruel or other mucil- 

 aginous fluid. To preserve its activity charcoal must be 

 kept dry and clean. Raised to a low red-heat shortly before 

 it is used, gases and organic matters are burned out of its 

 pores, and its efficacy is much increased. The charcoal 

 fouled in sugar-refining and other processes is thus cleansed 

 for repeated use. 



