CORTEX MARGOSiE. 155 



parcnchyme interwoven with small bands of corky tissue, — secondly 

 a dark cellular layer, and then the foliaceous liber. The dry bark 

 is inodorous and has a slightly astringent bitter taste. 



Microscopic Structure — The suberous coat consists of numerous 

 layers of ordinary cork- cells, which cover a layer of nearly cubic 

 sclerenchymatous cells. This latter however is not always met with, 

 secondary bands of cork {rhytidoma) frequently taking its place. The 

 liber is commonly built up of strong fibre-bundles traversed hy narrow 

 medullary rays, and transversely separated by bands of parenchy- 

 matous liber tissue. Crystals of oxalate of calcium occur in the 

 parenchyme more frequently than the small globular starch grains. 

 The structure of the bark varies considerably according to the gradual 

 development of the secondary cork-bands. 



Chemical Composition — Margosa bark was chemically examined 

 m India by Cornish^ (1856), who announced it as a source of a bitter 

 alkaloid to which he gave the name of Aiargosine, but which he ob- 

 tamed only in minute quantity as a " double salt of Margosine and 

 Soda,'' in long white needles. 



From the bitter oil of the seeds he isolated a substance which he 

 called Margosic Acid, and which he doubted to be capable of affording 

 crystallizable salts. The composition neither of this acid nor of margo- 

 sine IS known, nor have the properties of either been investigated. 



The small sample of the bark at our disposal only enables us to add 



^ an infusion produced with perchloride of iron a blackish preci- 



that 



pitate, and that an infusion is not altered by tannic acid or iodohy- 

 drargyrate of potassium. If the inner layers of the bark are alone 

 exhausted with water, the liquid affords an abundant precipitate with 

 tannic acid ; but if the entire bark is boiled in water, the tannic matter 

 ^hich it contains wdll form an insoluble compound with the bitter 

 principle, and prevent the latter being dissolved. It is thus evident 

 that to isolate the bitter matter of the bark, it would be advisable to 

 ^'ork on the liber or inner layers alone, which might readily be done, 

 as they separate easily. 



. -According to the recent researches of Broughton^ the bitter principle 

 js an amorphous resin soluble in the usual solvents and in boiling solu- 

 "ons of fixed alkalis. From the latter it is precipitated by acids, 

 yet, probably, altered. Broughton ascribed the formula C^^H^O'^ to 



nis bitter resin purified by means of bisulphide of carbon, ether 

 ana absolute alcohol; it fused at 92° C. He obtained moreover 

 f Jr 1 ^^^^'^i^^y of a crystallized principle, which he believed to be a 



atty body, yet its meltincj point of 175° C. is not in favour of this 

 suggestion. "^ ^ 



Uses— In India the bark is used as a tonic and antiperiodic, both 

 } natives and Europeans. Dr. Pulney Andy of Madras has found the 

 leaves beneficial in small-pox. 



cutfn'^'^'^'^-^""^^'^ O/'^^^f^'ca^iSacHce, Cal- ^ Madras Monthly Joimu MccL Science, 



^' 1^- (1857) 104. quoted in Phar in, Journ. June 14, 1873, 992. 



