EUONYMUS 243 



is secreted in laticiferous cells in the bast, and is found in all species 

 of Euonymus. 



The section, which is of a greyish white colour, exhibits, when 

 moistened, a narrow whitish cork, a pale cortex, and darker bast. 



The bark has a faint but characteristic odour recalling that of 

 liquorice root, and a disagreeable and persistent, bitter, acrid taste. 



Microscopical Characters. The transverse section exhibits a thick layer 

 of narrow cork cells, a cortex containing abundant cluster crystals of calcium 

 oxalate and a wide layer of secondary bast in which small cells filled with a 

 granular substance are scattered. The bark contains no bast fibres or sclerenchy- 

 matous cells. The medullary rays are one cell wide. 



The student should observe 



(a) The spongy grey cork, 



(b) The characteristic silky threads from the fractured surface, 



(c) The bitter taste. 



Constituents. A bitter, crystalline alcohol, euonymol (C 21 H 30 O 4 ), 

 has been isolated from it. From the resin (3-2 per cent.) contained 

 in it the crystalline alcohols euonysterol, homoeuonysterol, atropurol 

 and citrullol have been separated. 



The bark also contains considerable quantities of dulcitol (dulcite), 

 C 6 H 8 (OH) 6 , a hexatomic alcohol readily crystallising in large plates 

 melting at 188-5 ; it has a sweetish taste and has been found 

 in a considerable number of plants. The presence of the crystalline 

 glucoside euonymin has not been confirmed. 



Uses, Euonymin (the powdered extract) is an hepatic stimulant, 

 direct cholagogue, and mild cathartic. It is used in constipation and 

 in hepatic derangements. 



Substitutes. The stem-bark, which, although not official, is a 

 commercial article, occurs in long thin narrow strips ; it has a dark 

 greenish grey cork, green cortex, and fibrous bast ; it is therefore 

 easily distinguished from the root-bark. 



Wafer Ash bark, Ptelea trifoliata, Linne (N.O. Rutacece) has been 

 frequently mixed with or substituted for euonymus bark ; it is 

 thicker, bears long, transverse, whitish scars ; medullary rays three 

 cells wide ; below the cork a layer of yellow sclerenchymatous cells ; 

 in the secondary bast large oleo-resin cells. 



ALDER BUCKTHORN BARK 



(Cortex Rhamni Frangulse) 



Source, &C. The alder buckthorn, Rhamnus Frangula, Linne 

 (N.O. Rhamnece), is distributed generally over Europe. It is 

 distinguished from the common buckthorn (JR. catharticus, Linne), 



