274 R. T. BAKER. 



9. Bark. 



This investigation goes to show that all previous pub- 

 lished information (infra) stating that the bark is used 

 for tanning does not apply to the Australian species, as the 

 outer bark on very young and fully matured trees is so 

 thin and the quantity so small that it would never pay to 

 use it for tanning purposes. The tannin which it con- 

 tains does not amount to more than 7 per cent, according 

 to an analysis made by Mr. H. G. Smith. This goes to 

 show conclusively that, when it is spoken of — and it often 

 is— as a valuable tannin bark, several species must have 

 been or are included under the specific name. In fact, this 

 one feature alone seems to prove that we have here a dis- 

 tinct and very probably an unnamed species. 



Evidently the following data, appearing under the name 

 of Avicennia officinalis, do not apply to the Australian 

 species: — 



"The bark is astringent and is used by tanners." — ( Pharmaco- 

 graphia Indica," Vol. ill, p. 82, — Dymock). 



"The bark is used as a tanning agent." — ( Birdwood, Bombay, 

 Prod.) 



"In Rio de Janeiro, the barks of various species of Avicennia 

 are used in tanning leather." — (Dictionary of the Economic Pro- 

 ducts of India," Vol. I, p. 361,— Watt). 



"The next important group are the Mangroves, that grow in 

 the tidal creeks, which are said to make most durable sole leather, 

 even better than oak, but there appears to be a prejudice against 

 this tannin in England." — (Tropical Agriculturalist, Colombo," 

 1903-4, p. 2). 



"Fair percentage of tannin in this bark." — (New Plants in 

 Natal," 1905, Sims). 



"The bark is used in tanning." — (The Forests and Forest Flora 

 of Cape Colony, p. 287, — Sims). 



