FRUCTUS PRUNI. 251 



fact has been confirmed by Ernst of Caracas/ near which place the 

 plant abounds. Mr. Prestoe of the Botanical Garden, Trinidad, informs 

 us (1874) that in that island a convolvulaceous ipl&nt, Ipomcea disseda 

 Willd., contains a juice with a strong prussic acid odour. According to 

 Losecke, a common mushroom, Agaricus oreades Bolt., emits hydro- 

 cyanic acid.^ 



This acid is consequently widely diffused throughout the vegetable 

 kingdom. Yet amygdalin has thus far only been isolated from a few 

 plants belonging to the genus Prunus or its near allies.^ In all other 

 plants in which hydrocyanic acid has been met with, we know nothing 

 as to its origin. Ritthausen and Kreusler (1871) have proved the absence 

 of amygdalin in the seeds of a Vicia, which yield bitter almond oil and 

 hydrocyanic acid. These chemists followed the process which in the 

 case of bitter almonds easily afibrds amygdalin. 



Commerce — See preceding article. 



Uses — Bitter almonds are used almost exclusively for the manu- 

 facture of Almond Oil, while from the residual cake is distilled Bitter 

 Almond Oil. An emulsion of bitter almonds is sometimes prescribed 

 as a lotion. 



Adulteration — The adulteration of bitter almonds with sweet is a 

 frequent source of loss and annoyance to the pressers of almond oil, 

 whose profit largely depends on the amount of volatile oil they are 

 able to extract from the residual cake. 



FRUCTUS PRUNI. 



Prunes; F. Pi'UTieaux d medecine. 



Botanical Origin — Pninus doniestica L., var. ^. Juliana DC. — It 

 is from this tree, which is known as Prunier de St. JuLien,^ that the 

 true Medicinal Pi-unes of English pharmacy are derived. The tree is 

 largely cultivated in the valley of the Loire in France, especially about 

 Bourgueil, a small town lying between Tours and Angers. 



History — The plum-tree (P. doniestica L.) from which it is sup- 

 posed the numerous cultivated varieties have descended, is believed to 

 occur in a truly wild state in Greece, the south-eastern shores of the 

 Black Sea (Lazistan), the Caucasus, and the Elburz range in Northern 

 Persia, from some of which countries it was introduced into Europe 

 long before the Christian era. In the days of Pliny, nimierous species 

 of plum were already in cultivation, one of which afforded a fruit 

 ha\'ing laxative properties. 



Dried prunes, especially those taking their name fi-om Damascus 

 {Pi'una Damascena), are frequently mentioned in the writings of the 

 Greek physicians, by whom as well as at a later period by the practi- 

 tioners of the Schola Salemitana, they were much employed. 



In the older London pharmacopoeias, many sorts of plum are 



* Archiv der Pharmacie, 181 (1867) 222. * Loiselenr-Deslongchamps et Michel, 



- /a/oesftericAfofWiggersandHusemann Nouveau Duhamel, ou Trait4 des arhres et 



for 1871. 11. arbusteaque Fon cultive en France, v. (1812) 



^ Gmelin, Chemistry, \ni. 389; xv. 422. 189, pi. 51. fig. 2, pi. 56. fig. 9. 



