'2\^ LEGUMINOS^. 



year 174;6,\vben it was introduced into the London Pharmacopceiaui] ' r 

 the name of Lir/niim tinctile Campechense. 



Description — The tree is fit to be felled Avhen about ten years old; 

 the dark bark and the yellowish sap-wood are chipped off, the steuis 

 cut into logs about three feet long, and the red heart-wood aL«v 

 exported. By exposure to air and moisture, the wood acquires ext<'r- 

 nally a blackish red colour ; internally it remains brownish red- I: 

 splits well, although of a rather dense and tough texture. 



The transverse section of a piece of logwood exhibits to the naked 



eye a series of \ 

 large pores, and 



large 



and darker rings of the proper woody tissue. The numerous medul 



lary rays are visible only by means of a lens. The wood has a p 

 odour. 



asai 



orm 



of 



*.*.vi^^ovu^iij Structure — Under a high magnifying power, tn 

 concentric zones are seen to run not quite regularly round the centre, 

 but m a somewhat undulating manner, because they do not corrcspon'l 



vascul 



•nly 



th. 



nnitt'u 



by small lighter parenchymatous bands. The latter are made up ol 



stal of 



large, cubic, elongated or jiolygonal cells, each loaded with a crystal ( 

 oxalate of calcium. The large punctuated vessels having frcqueui" 

 loO mkm. diameter, are surrounded by this woody parenchyme, wm'e 

 the prevailing tissue of the wood " ^ - ^ -i- -.l-p.i 



^/< 



prosenchyme, consisting of long cylindrical 

 Clark red-brown walls having small pores. 



ihe medullary rays are of the usual structural character, runnmo 

 transversely in one to three straight rows ; in a longitudinal section. 

 the single rays show from 4 to 40 row« snprpprlincr each other perpen- 

 dicularly. No regular arran 



tudinal section made in a tangential direction. The colouring niaua 

 IS chiefly contained in the walls of the ligneous tissue aud the ves8*^ 

 and sometimes occurs in crystals of a greenish hue within the latter, or 



in clefts of the wood. 



alvsi? by 



Chemical Composition— Logwood was submitted to a^alp^^^ 

 Uievreul as early as the year lS10,i since which period all coning" 

 tions to a knowledge of the drug refer exclusively to its coloun"= 

 principle Ilccmatoxylin, which Chevreul obtained in a cry^^t^li- 

 state and called Ilematine. The very interesting properties otjn 

 Htlwis^s'so ^''''' ""^''"^^ examined by Erdmann (18i2) and byu- 



h^.^jf ""'T ^^^^^ed from logwood 9 to 12 per cent, of ^^^^t'I 

 nu r.^?'^^"- ^^'^"^^ ^'^ «^^^^d to have the formula C^H;*0 • l^^ * 

 W.W V- '' ^^^l^^^rlcss, crystallizing with 1 or with 3 eqmvalen^ 

 ^ater, and is readily soluble in hot water or in alcohol, but sparm.'. 



^ AnnaU ih Chimie, Ixxxi. (1812) 128. 



