CORTEX MEZEREI. 541 



unpleasant odour which is lost in drying ; its taste is persistently 

 burning and acrid. Applied in a moist state to the skin, it occasions, 

 after some hours, redness and even vesication. 



Microscopic Structure — The cambial zone is formed of about ten 

 rows of delicate unequal cells. The libre consists chiefly of simple fibres 

 alternating with parenchymatous bundles, and traversed by medullary 

 rays. The fibres are very long, — frequently more than 3 mm., and from 

 5 to 10 mkm. in diameter, their walls being always but little thickened. 

 In the outer part of the liber there occur bundles of thick-walled bast- 

 tubes, while chlorophyll and starch granules appear generally through- 

 out the middle cortical layer. The suberous coat is made up of about 

 30 dense rows of thin-walled tabular cells, which examined in a tan- 

 gential section, have an hexagonal outline. Small quantities of tannic 

 matter are deposited in the cambial and suberous zones. 



Chemical Composition — The acrid principle of mezereon is a 

 resinoid substance contained in the inner bark; it has not yet been 

 examined. The fruits were found by Martins (1862) to contain more 

 than 40 per cent, of a fatty, vesicating oil, which appears to be likewise 

 present in the bark. 



The name Daphnin has been given to a crystallizable substance 

 obtained by Vauquelin in 1808 from Dcvphne alpina, and afterwards 

 found by C. G. Gmelin and Baer in the bark of D. Mezereumi. Zwenger 

 in 1860 ascertained it to be a glucoside of bitter taste, having the 

 composition C^IT^O^ 4- '-^ OH", the same as that of -^sculin, the 

 fluorescing principle occurring in the bark of jEsculiis Hippocas- 

 tanum and the root-bark of Gelsemiimn nitidurn Michaux (G. seni- 

 'pei^ireiis Alton). — Cocco^r^iw?, isolated in 1870 by Casselmann from the 

 fruits of D. Mezereum, appears to be closely allied to if not identical 

 with daphnin. 



When daphnin is boiled with dilute hydrochloric or sulphuric acid, 

 it furnishes Daphnetin, C^H*50* -|- 0H-, described by Zwenger as 

 crystallizing in colourless prisms. By dry distillation of an alcoholic 

 extract of mezereon bark, the same chemist obtained Umbelliferone 

 (p. 322). 



Uses — Mezereon taken internally is supposed to be alterative and 

 sudorific, and useful in venereal, rheumatic and scrofulous complaints ; 

 but in English medicine it is never now given except as an ingredient 

 of the Compound Decoction of Sarsaparilla. An ethereal extract of 

 the bark has been introduced (1867) as an ingredient of a powerful 

 stimulating liniment. On the Continent, the bark itself, soaked in 

 vinegar and water, is applied with a bandage as a vesicant. 



Substitutes — Owing to the difficulty of procuring the bark of the 

 root of £>. Mezereum, the herbalists who supply the London druggists 

 have been long in the habit of substituting that of D. Laureola L., an 

 evergreen species, not uncommon in woods and hedge-sides in several 

 parts of England. The British Phai'macopceia (1864 and 1867) permits 

 Cortex Mezerei to be obtained indiscriminately from either of these 

 species, and does not follow the London College in insisting on the 

 hark of the root alone. That of the stem of D. Laureola corresponds in 

 structure with the bark of the true mezereon, but wants the prominent 



