FOLIA BUCHU. 109 



[folia 



Each kind is always imported by itself. Those of B. hetulina are the 

 least esteemed, and fetch a lower price than the others, yet appear to 

 be quite as rich in essential oil. 



Buchu leaves have a penetrating peculiar odour and a strongly 

 aromatic taste. 



Microscopic Structure — The essential oil is contained in large 



cells close beneath the epidermis of the under side of the leaf. The oil- 



cells are circular and surrounded by a thin layer of smaller cells; they 



consequently partake of the character of the oil-ducts in the aromatic 



roots of Umhelliferm and Cimiiiositce. The latter, hoM-ever, are 

 elongated. 



_ The upper side of the leaf of Barosma exhibits an extremely 

 interesting peculiarity.' There is a colourless layer of cells separating 

 the epidermis from the green inner tissue (mesophyllum). If the leaves 

 a^e examined under alcohol or almond-oil the coloindess layer is seen to 

 be very narrow, and the thin walls of its cells shrunken and not clearly 

 (ustmguishable. If the transverse sections are examined under water, 

 these cells immediately swell up, and become strongly distended, giving 

 ott an abundance of mucilage, the latter being afforded by the solution 

 ot the very cell-walls. The mucilage of buchu leaves thus originates 

 mthe same way as in flax seed or quince seed, but in the former the 

 ^piclernus is thrown off without alteration. We are not aware that 

 of ?! "^"^^^^oinous leaves possess a similar structure, at least not those 

 ^^f/'fea officinalis and of Sesamum which we examined.^ 



1- ^'"sniical Composition — The leaves of B. hetuliva afforded us by 

 u^tuiation 1-56 per cent, of volatile oil,' which has the odour rather of 

 Wermmt than of buchu, and deviates the ray of polarized light 

 1 . , ^^^bly to the left. On exposure to cold it furnishes a camphor 

 for^*^ ^' ^ a"^^ ^e-solution in spirit of wine, crystallizes in needle-shaped 

 D /■ -^j^^^ repeated purification in this manner, the crystals of 

 at 8-^n^ ^'^''njyhor have an almost pure peppermint odour; they fuse 



solidif ^1^*^ ^^^^^ cf^^^ sublime at 110° C. After fusion they again 

 crv^.i 7 ^^,-^ ^^ ^0° C. Submitted to elementary analysis, the 



of hvd ^2 i ^^ ^^"^^ P®^ ^^^*- °^ carbon and from 9 to 10 per cent, 

 of carh^^^^^ Barosma camphor is abundantly soluble in bisulphide 



a boil' ^^^. ^^^ from which the camphor has been separated has 

 That \vh-T^*-°^. ^^°^^* ^^^° ^•' quickly rising to 210'' or even higher, 

 ^diun ^^ ^^^^^^ijled between these temperatures was treated with 



m 



ffas 



];.:i'"^?gen. The 



^^ '^l^f hydrogen 



'H^^O would require 78 



\Xi 



^ym s experiments'' appear to indicate that the oil also contains 



.' Fliicki 



^^rm. Deo I's-o •''^" ^^^^'^'^"■'^''^triftfiir —Baroxma aerratlfoUa appears to be less 



S ' ^ee also Ra lIwT''^' ^''^**'- "'^^' according to Bedford (1863). 



^P"^hceen-G L ^ ^^> Monoyraphie der ■* Our supply of the substance having been 



'^' p. 10()_jQ- '"^ Serjania, Miinchen, exhausted by two analyses we cannot re- 



Messrs \lle* j gard the above figures as sufficient for the 



**'* larger qnani-iK i ^^^urys operating calculation of a formula. 



-1 "titles obtained 1 -63 per cent. « Am. Journ. ofPhar 



* Am. Journ. of Pharm. 1S70. 19. 



