438 DRIED JUICES 



KINO 



(East Indian, Malabar, Madras, or Cochin Kino) 



Source, &c. The term ' kino ' or ' kano ' was first applied to a red 

 astringent substance imported from West Africa about the middle of the 

 eighteenth century. This was obtained from Pterocarpus erinaceus, 

 Poiret. It was, however, soon replaced by other similar astringent 

 drugs, and the term ; kino ' became a generic one. The official drug, 

 although often spoken of as ' kino,' is better termed Malabar or Cochin 

 kino. Malabar kino is the juice obtained from incisions in the trunk of 

 Pterocarpus Marsupium, Roxburgh (N.O. Leguminosce) , evaporated to 

 dryness. The bast of the tree, which grows in southern India and Ceylon, 

 contains, according to v. Hohnel, numerous comparatively wide and 

 short tubular cells arranged in axial rows ; these cells are filled with 

 a red astringent liquid, which flows from them when they are wounded. 

 Vertical incisions, with oblique lateral ones running into them, are 

 accordingly made in the bark ; the juice that flows is collected in small 

 cups made of leaves, or in other convenient receptacles, and soon dries 

 in the sun to a dark mass that readily breaks up into small angular 

 grains. It is sometimes boiled before it is evaporated, an operation 

 that modifies the subsequent behaviour of the drug. Kino is occasion- 

 ally imported as a treacly liquid which can easily be dried. 



Description. Kino occurs in small, glistening, angular grains that 

 appear quite black and are remarkably free from dust. When thin 

 laminae or the edges of the grains are examined they are seen to be 

 transparent and of a dark ruby-red colour. They are hard and brittle, 

 breaking with a vitreous fracture and yielding a brownish red powder. 

 The drug is odourless, but has, when chewed, an astringent taste, and 

 adheres to the teeth, colouring the saliva red. 



In cold water kino is only partially (from 80 to 90 per cent.) soluble ; 

 it dissolves to a greater extent in hot water, and is almost entirely 

 soluble in alcohol. The aqueous solution turns green on the addition 

 of a ferrous salt, violet with an alkali, and throws down a precipitate 

 (kinotann^c acid) when acidified with a mineral acid. 



The student should particularly observe 



(a) The brilliant, apparently black, colour, 

 (6) The absence of any dust ; 



and should compare the drug with red gum. 



Constituents. The principal constituent of kino is kinotannic acid, 

 of which it contains from 70 to 82 per cent. The published assays 

 vary from 50 to 96 per cent., but this variation is probably due partly 

 to variation in the drug, partly to variation in the process adopted 

 for the assay, and partly to the gradual production of oxidation pro- 



