FLORES KOSO. 257 



History — The celebrated Bruce' during his journey to discover the 

 source of the Nile, 1768-1773, found the koso tree in Abyssinia, ob- 

 served the uses made of it by the natives, and published a figure of it 

 in the narrative of his travels. It was also described in 1799 by 

 Willdenow who called it Hagenia in honour of Dr. K. G. Hagen of 

 Konigsberg. 



The anthelmintic virtues of koso were investigated by Brayer, a 

 French physician of Constantinople, to which place parcels of the drug 

 are occasionally brought by way of Egypt, and he published a small 

 pamphlet on the subject.- Several scattered notices of koso appeared 

 in 1839-41, but no supply of it reached Europe until about 1850, 

 when a Frenchman who had been in Abyssinia obtained a large stock 

 (1,400 lb., it was said), a portion of which he endeavoured to sell in 

 London at 35s. per ounce ! The absurd value set upon the drug pro- 

 duced the usual result : large quantities were imported, and the price 

 gradually fell to Ss. or 4s. per lb. Koso was admitted a place in the 

 British Pharmacopoeia of 1864. 



Description — The flowers grow in broad panicles, 10 to 12 inches 

 in length. They are unisexual, but though male and female occur on 

 the same tree, the latter are chiefly collected. The panicles are either 

 loosely dried, often including a portion of stalk and sometimes a leaf, 

 or they are made into cylindrical rolls, kept in form by transverse 

 ligatures. Very often the panicles arrive quite broken up, and with 

 the flowers in a very fragmentary state. They have a herby, some- 

 what tea-like smell, and a bitterish acrid taste. 



The panicle consists of a zigzag stalk, which with its many 

 branches is clothed with shaggy simple hairs, and also dotted over with 

 minute stalked glands ; it is pro\dded at each ramification with a 

 large sheathing bract. At the base of each flower are two or three 

 rounded veiny membranous bracts, between which is the turbinate 

 hairy calyx, having ten sepals arranged in a double series. In the 

 male, the outer series consists of much smaller sepals than the 

 inner ; in the female, the outer in the ultimate development become 

 enlarged, obovate and spreading, so that the whole flower measures 

 fully ^ an inch across. In both, the sepals are veiny and leaflike. The 

 petals are minute and linear, inserted with the stamens in the throat 

 of the calyx. These latter are 10 to 25 in number, with anthers in 

 the female flower, efiete. The carpels are two, included in the caly- 

 cinal tube ; and each surmounted by a hairy style. The fruit is an 

 obovate one-seeded nut. 



Koso as seen in commerce has a light brown hue, with a reddish 

 tinge in the case of the female flowers, so that panicles of the latter are 

 sometimes distinguished as Red Koso. 



Chemical Composition — Wittstein (1840) found in koso, together 

 with the substances common to most vegetables (wax, sugar, and gum), 



^ Travels, v. (1790) 73. for sale in London. Pharm. Journ, x. 



^ Notice sur une nouvelle plante de la (1851) 15; reprinted in Pereira's Elem. of 



famille des BosacSes, employee centre le Mat. Med. ii. part 2 (1853) 1815. — Also 



Ttenia, Paris, 1822. The reader should Meyer-Ahrens, Die BlUthen des Kosso- 



also consult the excellent notice by Pereira baumes, Zurich, 1851. 90 pp. 

 written when the drug was first oflFered 



