372 INDIAN MEDICINAL PLANTS. 



ceolate, long, acuminate, entire, thinly coriaceous, usually quite 

 glabrous, lateral nerves 8-15 pair, alternating with shorter in- 

 termediate ones ; base rounded acute or oblique, petiolules 

 slender, 5-fin. long. Panicles axillary, with slender and 

 drooping ramifications, much shorter than the leaves. Flowers 

 pedicelled, scarcely i^in. diam., greenish yellow. Sepals 

 ovate-obtuse. Petals much larger, oblong or obtuse. Disk 

 5-lobed. Drapes Jin. diam., compressed, glabrous, rugose, 

 yellow or light brown; epicarp thin, bursting irregularly. 

 Mesocarp fibrous. Kernel compressed, hard, surrounded by 

 a vegetable wax (Kanjilal), " mixed with the fibre," adds 

 Brandis. 



Use : — The juice of the leaves is said to blister the skin 

 (Stewart). The fruit is considered officinal and is used in Kash- 

 mir in the treatment of phthisis. 



Chemistry.— The sap is a thick, nearly white, alkaline cream, superficially 

 oxidisable by air to an intensely black, impervious susbtance, insoluble in 

 the usual solvents. 



Complete oxidation only takes place in the presence of a diastatic 

 ferment, laccase, which can be separated from the other essential constituent 

 of the sap by means of alcohol, in which it is insoluble. When precipitated 

 by alcohol from aqueous solution, the crude laccase dries to white, opaque 

 fragments, like gum, and is probably a mixture of the ferment with carbo- 

 hydrates, as it can be oxidised to mucic acid, and hydrolysed to galactose 

 and arabinose. 



From the portion of the sap soluble in alcohol, a substance, laccol, 

 probably a polyphenol, can be precipitated by lead acetate. It is a thick 

 oil, insoluble in water, but soluble in alcohol, &c, and is intensely irritating 

 to the skin, as is the crude sap. Laccol is readily oxidisable in the air to a 

 reddish, viscous, or resinous substance ; in alkaline solution, it behaves 

 like pyrogallol, blackening and absorbing oxygen with such rapidity as 

 to become hot ; it reduces ferric chloride in alcoholic solution, forming 

 a black, metallic derivative. 



When laccol is precipitated from alcoholic solution by an aqueous 

 solution of laccase, the white emulsion rapidly blackens from absorption of 

 oxygen ; but this does not take place if the laccase solution has been boiled, 

 or if water alone is the precipitant. The action of laccase on gallic acid 

 &C, is similar, the rate of absorption of oxygen being enormously increased. 

 As the ferment has no action on starch, sugar, amygdalin, &c, it seems to be 

 the first member of a new class of " oxidising diastases." 



Since laccase is present in many plants, it seems not improbable that 

 this diastase plays an important part in the respiration of plants, 



J.Ch.S. 1895 Alp. 386. 



