99 PRUNUS AMYGDALUS 



of a specific gravity varying from 0*912 to 0*920, and when fresh 

 it is almost or entirely inodorous, and has a mild, oleaginous, 

 nutty taste. It congeals less readily than olive oil. It is com- 

 posed almost wholly of oleic acid combined with glycerin. It 

 soon becomes rancid by exposure to the air. 



Medical Properties and Uses. Almond oil possesses the medi- 

 cinal and dietetical properties of fixed oils generally. When 

 applied locally it is emollient, and when taken in small quantities 

 it is nutritive, and in large doses laxative. It may be employed 

 for the same purposes as olive oil, and when made into an emulsion 

 with mucilage, or yolk of eggs and sugar, it may be used in 

 allaying troublesome cough, &c. 



In pharmacy it is employed in the preparation of several of the 

 official ointments. 



4. OLEUM AMYGDALA AMAR^]. Volatile Oil of Sitter Almonds. 

 This oil has already been referred to under the head of Amygdalae 

 Amarse as resulting from the decomposition of amygdalin under 

 the influence of emulsin and water, and stated to be obtained by 

 submitting the bitter almond cake left after the expression of the 

 fixed oil to distillation with water, either alone or more commonly 

 with salt. The yield of volatile oil, as shown by the experiments 

 of Umney, is liable to great variation, the amount obtained by 

 him being, in some cases, as much as 0*95 per cent., while in 

 others it was only 0*42 per cent. This volatile oil is a mixture 

 or compound of various substances, as hydride of benzoyl, hydro- 

 cyanic acid, benzoine, and benzamide, and is commonly known as 

 crude oil of bitter almonds. It is this oil which is official in the 

 Pharmacopoeia of the United States. It has a golden-yellow colour, 

 and varies in sp. gr. from 1*052 to 1*082. Umney gives it from 

 1*061 to 1*065. This crude oil is highly poisonous on account of 

 the hydrocyanic acid which it contains, the proportion of which, 

 however, varies from 8 to 14 per cent. The hydrocyanic acid is 

 frequently separated by manufacturers from the crude oil, and the 

 oil is then supplied as oil of bitter almonds free from hydrocyanic 

 acid, or purified oil of bitter almonds. Various processes have 

 been given by different chemists for the separation of hydrocyanic 



