LINIMENTS PASTES 727 



generally employed are lard and oils ; greater consistence 

 and adhesion are conferred by addition of paraffin wax or 

 resin : rancidity is checked by admixture of benzoin, or by 

 substituting mineral, for animal or vegetable oils. By using 

 hydrous wool fat, or oleic acid as the basis, absorption 

 through the skin is said to be facilitated. When lard or 

 oil is the excipient, the ointment may generally be prepared 

 in a suitable mortar ; but when wax or resin is used, it must 

 be melted over a slow fire, the other constituents added, and 

 the mass stirred until it has acquired proper consistence. 

 Ointments, of which forty-four are enumerated in the B.P., 

 should be kept in well-closed pots or jars, which (except 

 when in daily use) should be covered with moistened 

 bladder and strong paper. They are generally dispensed 

 either in chip boxes or earthenware pots, of which the 

 practitioner should have several sizes. In dispensing these 

 and other officinal preparations, spatulse of steel, bone, wood 

 or horn are essential articles of the pharmacy. 



Oleates are solutions of active principles in oleic acid. 

 The B.P. contains directions for making mercuric oleate 

 and the ointments of mercuric and zinc oleates. Oleic 

 acid is used in the preparation of the ointments of cocaine, 

 atropine, aconitine, and veratrine. Oleates are sometimes 

 preferred to the corresponding ointments, on account of 

 their being more readily absorbed. The smart friction 

 employed in the in-rubbing of this class of remedies is 

 itself of considerable therapeutic value. It causes dilata- 

 tion of cutaneous capillaries, and hence promotes increased 

 circulation through superficial blood and lymph vessels. 



Liniments or embrocations are solutions of active prin- 

 ciples in oil or spirit ; some, besides, contain camphor, 

 several have soap added, to increase their lubricant pro- 

 perties ; all are intended for external use. The B.P. 

 enumerates fifteen liniments. 



Pastes are topical applications, of which the basis consists 

 wholly or partially of fine silica, magnesium carbonate, or 

 siliceous earths. Zinc oxide and other ointments are some- 

 times united with ten per cent, of such siliceous matters. 

 The term ' paste ' is occasionally also applied to mixtures of 

 farina or flour with such drugs as borax, alum, or zinc oxide. 



