574 EUPHORBIACE^. 



great trading station between the Galla countries and Berbera.^ Yet 

 the Arabian and African drug consists in most cases not of kamala, but 

 of those dark glands which we describe further on, at p. 575. 



Description — Kamala is a fine, granular, mobile powder, consisting 

 of transparent, crimson granules, the bright colour of which is mostly 

 somewhat deadened by the admixture of grey stellate hairs, minute 

 fragments of leaves and similar foreign matter. It is nearly destitute of 

 taste and smell, but an alcoholic solution poured into water emits a 

 melon-like odour. Kamala is scarcely acted on by water, even at a 

 boiling heat ; on the other hand, alcohol, ether, chloroform or benzol 

 extract from it a splendid red resin. Neither sulphuric nor nitric acid 

 acts upon it in the cold, nor does oil of turpentine become coloured by 

 it unless warmed. It floats on water, but sinks in oil of turpentine. 

 When sprinkled over a Hame, it ignites after the manner of lycopodiura. 

 Heated alone, it emits a slight aromatic odour ; if pure, it leaves after 

 incineration about 1'37 per cent, of a grey ash. 



Microscopic Structure — The granules of kamala are irregular 

 spherical glands, 50 to 60 mkm. in diameter ; they have a wavy surface, 

 are somewhat flattened or depressed on one side, and enclose within 

 their delicate yellowish membi'ane a structureless yellow mass in 

 which are imbedded numerous, simple, club-shaped cells containing a 

 homogeneous, transparent, red substance. These cells are grouped in a 

 radiate manner around the centre of the flattened side, so that on the 

 side next the observer, 10 to 30 of them may easily be counted, while 

 the entire gland may contain 40 to 60. In a few cases, a very short 

 stalk-cell is also seen at the centre of the base. 



When the glands are exhausted by alcohol and potash, and broken 

 by pressure between flat pieces of glass, the}^ separate into individual 

 cells which swell up slightly, while the membranous envelo})e is com- 

 pletely detached, and appears as a simple coherent film. After this 

 treatment the cells, but not their membranous envelope, acquire by 

 prolonged contact with strong sulphuric acid and iodine water a more 

 or less brown or blue colour: the wllas of the cells alone correspond 

 therefore to cellulose. Vogl (1864) supposes that a cell of the epidermis 

 of the fruit first developes a young cellule, which by partition is resolved 

 into the stalk-cell and the true mother-cell of the small clavate resin- 

 cellules. At first, the contents of the latter do not differ from the mass 

 in which they are imbedded, and perhaps pass gradually into resin by 

 metamorphosis of the cellular substance. 



The glands of kamala are always accompanied by colourless or 

 brownish, thick-walled, stellate hairs, two or three times as long as the 

 glands, often containing air, which do not exhibit an}'- peculiarity of 

 form, but resemble the hairs of other plants, as VerbascuTn or Althcea. 



Chemical Composition — Kamala has been analysed by Anderson 

 of Glasgow (1855) and by Leube (1860). From the labours of these 

 chemists, it appears that the powder yields to alcohol or ether nearly 

 80 per cent, of resin. We find it to be soluble also in glacial acetic acid 

 or in bisulphide of carbon, not in petroleum ether. By treatment of 

 the resin extracted by ether with cold alcohol, Leube resolved it into 



^ Burton, Joum. of R. Geo(jr. Society, Mittheilungen, Ergiinzungsheft, xlvii. (1874) 

 XXV. (1855) 146. Haggenmacher, Reise in 39. 

 daa Somaliland, in Petermann's Geofjr. 



