AD EPS. 377 



PACHYDERMATA. 



Adeps Prseparatns PREPARED LARD. The 

 purified fat of the Hog, Sus scrofa. 



Characters and tests. A soft white fatty substance, melting 

 at about 100. Has no rancid odour. Dissolves entirely in 

 ether. 



Impunities. Common salt and starch. 



Composition. Lard consists of 60 per cent, of olein, and 

 some palmitin and stearin. Olein is a fluid oil, a compound 

 of oleic acid, C l8 H3 3 O 2 , and glyceryl, C 3 H 6 . Palmitin and 

 stearin are solid oils, compounds of glyceryl -with palmitic 

 acid (CigHgaC^), and stearic acid (C^S^Oa) respectively. 



Preparations. 



1. Adeps Benzoatus. 1 of Benzoin in 64 of Lard. 



2. Unguentum Simplex. 3 in 8, with White Wax and Almond 



Oil. 



Either Lard or Benzoated Lard is contained in almost all 

 ointments. 



ACTION AND USES. 



Lard is a simple emollient, forming the basis of most of 

 the officinal ointments. Benzoated lard does not become 

 rancid like ordinary lard, which for the same reason is now in 

 a measure replaced by vaseline. 



CETACEA. 



Cetaceum SPERMACETI. Nearly pure cetine, 

 obtained, mixed with oil, from the head of the Sperm 

 Whale, Physeter macrocephalus, inhabiting the Pacific 

 and Indian Oceans. It is separated from the oil by 

 nitration and pressure, and afterwards purified. 



Characters. Crystalline, pearly white, glistening, translu- 

 cent, with little taste or odour, reducible to powder by the 

 addition of a little rectified spirit. Scarcely unctuous to the 

 touch ; does not melt under 100. 



Substance resembling Spermaceti : White Wax, known by 

 general appearance and hardness. 



Composition. Spermaceti is a fat, containing as its base, 

 not glycerin but cetylalcohol, in combination with palmitic acid. 



