364 SALIC IKE JE. 



of a blackish or bluish -green colour and heavy ; those from 

 which the insect has escaped are of much lighter colour, gene- 

 rally yellowish- white, on one side a i-ound hole may be perceiv- 

 ed ; they are also lighter in weight and less astringent. When 

 a gall is cut in two a *round cavity is seen in its centre, which" 

 may or may not be occupied by the insect ; in the latter case a 

 passage leads from the cavity to the exterior. 



Microscopic structure. — The contents of the central cavity, 

 if present, are seen to consist of a starchy parenchyme destined 

 to supply food to the larva. The walls of the cavity are formed 

 of stone-cells. The bulk of the gall consists of cells arranged 

 in a radiating manner, many of them containing colouring 

 matter and tannin. Towards the exterior of the gall the cells 

 contain dark-coloured chlorophyl ; on the very surface the 

 cells are small and thick-w^alled and form a kind of rind. 



Chemical eomposition. — The principal constituent of galls is 

 tannin or tannic acid. The tannin of different plants possesses 

 distinctive characters ; that obtained from galls is known as 

 gallo-tannic acid. It is identical with the tannin oi Rhus cori- 

 fiW'm, Linn. (Sumach), 



Galls afford from 60 to 70 per cent, of tannin, and about 

 2 per cent, each of gallic and ellagic acids. 



Commerce. — Grails are imported from Basra and the Persian 

 Gulf ports. Value: White, Rs. 10 per maund of 37^ lbs«; 

 Blue, Rs. 17. Imports about 1^400 cwts. yearly. 



SALIOINE^. 



SALIX CAPREA, Linn. 



Fig.— ^«gr. BoL, 1488; ReicM. FL Germ., t. 577. Great 



n 



round-leaved Sallow, Goats' Sallow {Eng.), Marceau, Marsault 

 (Fr.). 



Hab. — Persia, Europe. Cultivated in N.-W. India. The 

 "bart, leaves, seeds, and flowers. 



r^r«fl'n//jr.~Bedmishk (Indian Bazars). 



