110 RUTACE^. 



a substance capable of being converted into salicylic acid. An aqueous 

 infusion of buchu leaves turns beautifully yellow if it is mixed with 

 alkali. 



On addition of perchloride of iron the infusion assumes a dingy 

 brownish-green colour changing to red by an alkali. The infusion 

 added to a concentrated solution of acetate of copper causes a yellow 

 precipitate^ which dissolves in caustic potash, affording a green solution. 

 This may be due to the presence of a substance of the quercitrin or 

 rutin class. 



When the leaves are infused in warm water, the mucilage noticed 

 under the microscope may easily be pressed out. It requires for 

 precipitation a large amount of alcohol, being readily miscible with 

 dilute alcohol. Neutral acetate of lead produces a yellow precipitate 

 in an infusion of the leaves; the liquid affords a precipitate by a sub- 

 sequent addition of basic acetate of lead. The latter precipitate is 

 (probably) due to the mucilage, that afforded by neutral acetate partly 

 to mucilage and partly, we suppose, to rutin or an allied substance. 

 Yet the mucilage of buchu leaves is of the class which is not properly 

 dissolved by water, but only swells up like tragacanth. 



The leaves of B. crenulafa afforded us upon incineration 47 per 

 cent, of ash. Jones (1879) obtained on an average 454 per cent, from 

 the same species; 527 from B. serratifolia ; and 4'49 from B. befulina. 

 He pointed out the presence of manganate in this ash. 



The Diosmin of Landerer^ is entirely unknown to us. 



Commerce — The export of buchu from the Cape Colony in 1872 

 was 379,125 lb., about one-sixth of which quantity was shipped direct 

 to the United States.'' 



Uses — Buchu is principally administered in disorders of the urino- 

 genital organs. It is reputed diuretic and diaphoretic. In the Cape 

 Colony the leaves are much employed as a popular stimulant and 

 stomachic, infused in water, sherry, or brandy. They are also exten- 

 sively used in the United States, both in regular medicine and by the 

 vendors of secret remedies. 



Substitutes — The leaves of EmpleuruTn serrulatwni Ait., a small 

 shrub of the same order as Ba,rosma and growing in the same 

 localities, have been imported rather frequently of late and sold as 

 Buchu. They have the same structure as regards mucilage, and nearly 

 the same form as those of B. serratifolia, but are easily distinguished. 

 They are still narrower, and often longer than those of B. serratifolia, 

 devoid of lateral veins, and terminate in an acute point without an oil- 

 duct. They have a bitterish taste and a less powerful odour than those 

 of Barosma, even in fresh leaves as imported in London. The odour of 

 Empleurum is moreover distinctly different from that of the leaves of 

 Barosma. The flowers of JEmpleurum are still more distinct, for they 

 are apetalous and reddish brown. The fruit consisting of a single, 

 compressed, oblong carpel, terminated by a flat-shaped horn, is quite 

 unlike that of buchu. 



The leaves of Barosma Eckloniana Berg (regarded by Sonder* as 



^ It seems green as long as it is in the •''i?/?<e 5ooX- published at Cape Town, 1873. 



blue cupric liquid. * Harvey and Sender, Flora Capensis, i. 



2 Gmelm's Chemistry, xviii, 194. (1859-60) 393. 



