198 BvHKS. 



(97) Cusparia Bark. 



The bark of Galipea officinalis, Hancock (N.O. Rutacese). 

 The bark exhibits the following structure : 



(1) Cork. The characters of this tissue vary considerably in 

 different specimens. Frequently there is on the outside a more 

 or less extensive layer of thin-walled cells, and towards the in- 

 terior a layer of thick- walled cells ; or these conditions may be 

 reversed, or the thin-walled cork may be almost entirely absent. 

 In surface view the cork cells are polygonal in outline. 



(2) A narrow layer of phelloderm, the cells of which, in sur- 

 face view, also appear polygonal. 



(3) Cortex, composed of tangentially elongated parenchymatous 

 cells containing small, rounded starch grains. This tissue con- 

 tains large oval cells, in each of which there is a bundle of 

 acicular crystals of calcium oxalate ; it also contains oil glands, 

 and not unfrequently small groups of polygonal parenchyma- 

 tous cells with moderately thick, pitted walls. 



(4) Bast Ring, in which oil glands and small groups of bast fibres 

 can be distinguished. In this tissue crystal cells are also pre- 

 sent, but the cells themselves are not larger than the neighbour- 

 ing parenchymatous cells, and the calcium oxalate takes the 

 form of long, pointed, prismatic crystals. The bast fibres have 

 very thick walls, and are grouped together in bundles of mode- 

 rate size. The sieve-tubes are arranged in tangential bands, 

 which alternate with similar bands of bast parenchyma ; they 

 may be distinguished by having rather thicker walls, and in the 

 older parts of the bark are often collapsed. 



The medullary rays are two cells wide, near the cambium, but 

 enlarge towards the cortex. 



When a section is moistened with dilute solution of ferric 

 chloride a bright red colour is developed, especially near the oil 

 cells. 



The diagnostic characters of cusparia bark are : 



(a) The presence of acicular and prismatic crystals of 



calcium oxalate. 



(b) The oil glands. 



(c) The bast fibres. 



(d) The characteristic cork. 



(e) The red coloration with ferric chloride (not always 



well defined in the powder). 



