1918.] 
The N.Z. Journal of Science and Technology. 
34T 
also the puriri (Vitex lucens) dyes, concerning which A. G. Perkin,* after 
comparing them with old fustic (Morus tincloria ) and weld, stated that 
they may be of commercial utility on the English market on account of 
the pure-yellow fast tones they give. 
In the first instalment of this article attention was drawn to the 
individuality shown by different species of Coprosma, of which over forty 
occur in New Zealand, in the colour of the cortical tissue and of its reaction 
to alkali. The following table will indicate the nature of these variations ; 
twenty species are mentioned, and at least as many more remain to be 
examined. It will be seen that even the preliminary examination of the 
Coprosma genus will occupy some time longer. 
Table A. —Colour Reactions of Coprosma Barks (Cortex) when treated with 
a Few Drops of 10-per-cent. Sodium Hydrate. 
Colour of Cortex. 
Reaction. 
Coprosma grandifolia 
Light orange 
Port-wine red. 
C. lucida 
Canarv-yellow . . 
Crimson. 
C. Baueri 
White . . 
Nil. 
C. robusta 
99 • • 
Greenish-brown. 
C. Cunninghamii 
5? • • 
Greenish-yellow. 
C . rotundifolia 
Orange 
Light to dark red. 
C. areolata 
Dark brown 
Violet. 
C. tenuicaulis 
Yellow.. 
Blood--red. 
C. rhamnoides. . . . 
Greenish-yellow 
Orange. 
C. parviflora . . 
White . . 
Nil. 
C. Bichanani . . 
Stem, greenish-white; root, 
Stem, nil; root, crim- 
yellowish-red 
son. 
C. crassifolia . . 
Stem, white; root, yellowish 
Stem, nil; root, red 
to purple-red. 
C. acerosa 
Stem, yellowish-green; root, 
Stem, brownish-red;. 
yellow 
root, red to crimson. 
C. propinqua .. 
White . . 
Greenish-yellow. 
C. Kirkii 
White to yellowish near 
Pinkish-red to crim- 
cuticle 
son on j^ellowish 
cortex only. 
C. linariifolia 
Yellowish 
Red. 
C. foetidissima 
Greenish 
Yellow. 
C. Colensoi 
• "7 ‘ ji- I 
Pinkish-red. 
C. cuneata 
Brownish 
Red. 
C. microcarpa 
Stem, yellowish-green; root, 
Reddish - brown to 
yellow 
brick-red. 
There are certain qualities possessed by the better natural dyes which 
enable them to maintain a stand against the artificial dyestuffs. Two of 
these qualities are fastness and penetrability. The cheapness of the 
synthetic dyes is, however, proving the great factor in their favour. The 
late Dr. Sarah Baker’s stimulating and beautiful essay on vegetable dyes,f 
which should be read by every one interested in the subject, holds out the 
possibility that for certain standard colours for which there is a steady 
demand, especially where fastness is important, a vegetable crop may be 
the most effective source of supply, especially as regards the dark browns,, 
blues, purples, and blacks, the synthesis of which is always a complex 
process. 
*Journ. Agr., vol. 15, p. 125, Wellington, 1917 
t The Exploitation of Plants, 1917. 
