22 



Further, on decomposition with alkah' the colourids: matter yielded 

 phloroplucinol and prot ocatechnic acid. The amount of quercetin con- 

 tained in the leaves was approximately 0.3 per cent. The substance 

 accompanying the quercetin, soluble in alkalis with a green colouration, 

 could not be isolated owing to the small quantity present. It could 

 however be removed from the quercetin by treatment with bromine and 

 crystallising the product from alcohol. The debrora-quercetin thus ob- 

 tained melting at 232 ^ -234 ^ , was reconverted into quercetin by diges- 

 tion with hydriodic acid, and was now soluble in alkalis with a pure 

 yellow colouration. 



The Tannin. As experiment indicated the presence of a consid- 

 erable quantity of a tannin in these leaves, it was desirable to isolate 

 and submit this to examination. The leaves were extracted with boiling 

 alcohol, the extract evaporated to a small bulk, poured into water and 

 treated with ether to remove wax and chlorophyll. From the brown 

 aqueous liquid after saturation with salt the tannin was extracted with 

 ethylic acetate and thus obtained in the form of a sticky brown mass. This 

 was dissolved in water and the solution treated with salt, which caused 

 the precipitation of a viscous brown impurity which was removed by 

 agitation with bibulous paper and filtration. From the clear liquid 

 the tannin was removed by ethylic acetate, and on cautiously evapora- 

 ting this solution was now obtained as a pale yellow friable mass. An 

 analysis gave 0=53.15 ; H=4.02 numbers which are in close agree- 

 ment with those required bv gallo-tannic acid. As it gave a blue green 

 colouration with ferric chloride in aqueous solution, and gallic acid 

 by digestion with boiling dilute sulphuric acid its identity with this 

 substance was confirmed. Bromine water gave no precipitate indica- 

 ting the absence of a catechol tannin. 



The constituents of the leaves of Haematoxylon campeachianum are 

 thus quercetin, a trace of a second colouring matter which is probably 

 myricetin, and gallo-tannic acid. There is no direct relationship between 

 quercetin, the colouring matter of the leaves, and the haematoxylin 

 which exists in the stems ; on ihe other hand it is interesting to note 

 that both gallo-tannic acid and haematoxylin are derivatives of pyro- 

 gallol. 



The chemical examination indicated that these leaves might con- 

 stitute a serviceable tanning agent, and application was therefore made 

 to Professor Procter who kindly undertook to study their properties in 

 this respect. He reports as follows. 



Tanning matters absorbed by hide 9.5 per cent. 

 Soluble non-tanning matters 17.5 ^* 



insoluble at 60 ^ F. 62.8 " 



Water 10.4 " 



100.0 



The tanning strenth* 9.5 per cent, is too low to allow of their pro- 



* The sample of leaves employed was collected, for the author with no 

 special idea of their examination as a tanning agent, and evidently being 

 slightly brown at a somewhat late period of the season. As a sample of 

 selected leaves analysed by Professor Procter gave 11.2 per cent, of tanning 

 matter, it is to be presumed that if collected at a suitable period their tanning 

 content will be greater than that given above. 



