FOLIA LAURO-CERASI. 255 



of London^ to some cases of poisoning that had occurred by the use of a 

 distilled water of the leaves. This water he states had been for many 

 years in frequent use in Ireland among cooks, for flavouring puddings 

 and creams, and also much in vogue with dram drinkers as an addition 

 to brandy, without any ill effects from it having been noticed. The 

 fatal cases thus brought forward occasioned much investigation, but the 

 true nature of the poison was not understood till pointed out by 

 Schrader in 1803 (see art. Amygdalae amane, p. 248, note 2). Cherry- 

 laurel water, though long used on the Continent, has never been much 

 prescribed in Great Britain, and had no place in any British Pharma- 

 copoeia till 1839. 



Description — The leaves are alternate, simple, of leathery texture 

 and shining upper surface, 5 to 6 inches long by 1| to 2 inches wide, 

 oblong or slightly obovate, attenuated towards either end. The thick 

 leafstalk, scarcely half an inch in length, is prolonged as a stout midrib 

 to the recurved apex. The margin, which is also recurved, is provided 

 with sharp but very short serratures, and glandular teeth, which become 

 more distant towards the base. The under side, which is of a paler 

 colour and dull surface, is marked by 8 or 10 lateral veins, anastomosing 

 towards the edge. Below the lower of these and close to the midrib, 

 are from two to four shallow depressions or glands, which in spring 

 exude a saccharine matter, and soon assume a brownish colour. By the 

 glands with which the teeth of the serratures are provided, a rather 

 resinous substance is secreted.^ 



The fresh leaves are inodorous until they are bruised or torn, when 

 they instantly emit the smell of bitter almond oil and hydrocyanic 

 acid. WTien chewed they taste rough, aromatic and bitter. 



Microscopic Structure — The upper surface of the leaf is consti- 

 tuted of thin cuticle and the epidermis made up of large, nearly cubic 

 cells. The middle layer of the interior tissue exhibits densely packed 

 small cells, whereas the prevailing part of the whole tissue is formed 

 of larger, loose cells. Most of them are loaded with chlorophyll; some 

 enclose crystals of oxalate of calcium. 



Chemical Composition — The leaves when cut to pieces and sub- 

 mitted to distillation with water, yield Bitter Almond Oil and Hydro- 

 cyanic Acid, produced by the decomposition of Laurocerasin. This 

 is an amorphous yellowish substance isolated by Lehmann (1874) in 

 Dragendorlfs laboratory. He extracted the leaves with boiling alcohol, 

 and purified the liquid by gently warming it with hydroxide of lead. 

 From the liquid, crude laurocerasin was precipitated on addition of 

 ether ; it was again dissolved repeatedly in alcohol and precipitated by 

 ether. The yield of the leaves is about 1^ per cent. Laurocerasin is 

 readily soluble in water, the solution deviates the plan of polarization 

 to the left, yet not to the same amount as amygdalin. The molecule 

 of laurocerasin, C^H^NO*', would appear to include those of amygdalin, 

 C^H^NO", amygdalic acid, C^'IPO^^^ and 7 0H-. 



The proportion of hydrocyanic acid in the distilled water of the 

 leaves has been the subject of many researches. Among the later are 

 those of Broeker (1867), who distilled a given weight of the leaves 



1 PAiZ. Trans, xxxvii. (for 1731-32) 84. /fir wissenschaftliche Botanil; x. (1875) 



- Reinke, in Pringsheim's Jakrb'dcher 129. 



