NATURAL DYES AND COLORING MATTERS. 447 



Palladin -° and Miss Wheldale 30 are of the opinion that anthocyanin, the red 

 coloring matter of certain flowers, is formed by the action of an oxidase on some 

 chromogenic substance. Bertrand found an oxidase resembling laccase in the 

 Mowers of Gardenia. Such a substance is also present in the white and yellow 

 champaca flowers, Michelia alba L. and Michelia charnpaca L. This oxidase 

 turns tincture of guaiacum blue, develops the color of the Rohmann-Spitzer reagent 

 and oxidizes hydroquinone and phloroglucine. 



KHAKI DYES. 



Doctor Foxworthy, of the botanical laboratory of this Bureau, states 

 that the bark of Pterospermum niveum Vid., {baijog, Tag.) is used in 

 dying fish nets to a reddish-brown color. Some of the brown shades 

 produced on cotton fabrics by the Filipinos are quite fast. A search 

 through the literature reveals the fact that little is known about the 

 dyeing of khaki cloth outside of manufacturing establishments. The 

 majority' of the patents covering this process describe methods of im- 

 pregnating the cloth with iron; chromium, or manganese compounds. 31 

 There is no doubt that much khaki cloth is colored with coal-tar dyes. 



The value for tanning purposes of the cutch extracts from Philip- 

 pine mangrove barks has already been reported on by Bacon and G-ana. 32 

 The most highly colored extracts contain reddish-brown coloring mat- 

 ters, but when used alone these barks do not give true khaki shades. 

 In the past, cutch extracts have largely been used, with metallic mor- 

 dants, for dyeing khaki shades, but the synthetic dyes have entered this 

 field also. 



Good khaki shades were obtained from ipil wood, Intsia bijuga 0. 

 Ktze. The extract dyes cotton in neutral or slightly acid solution to 

 a clear, soft brown. Cotton mordanted with tin is colored to a brown 

 shade, having an olive tint. The colors axe quite fast to light and to 

 washing. Silk is dyed a beautiful, soft, brown shade. The coloring 

 matter reacts like a tannin, giving a black precipitate with ferric 

 chloride and an abundant flocculent precipitate with gelatin solution. 

 Owing to the limited supply of this wood and its value as building 

 material, its virtues as a dye wood were not further investigated. 



SAPPAjST wood. 



The dye wood which finds the most extensive use in the Philippines 

 is sappan wood from the species Ccesalpinia sappan L. 



Bolley 33 and Bacon ai have shown that this wood contains brasilin. Since 



-° Ber. d. deutschen bot. Ges. (1908), 26, 378. 

 s "Proc. Cambridge Phil. Soc. (1909), 15, 137. 



31 All of the samples of khaki examined in this laboratory have been dyed with 

 these metallic oxides. 



32 This Journal, Sec. A (1909), 4, 205. 

 m Joum. f. pralct. Chem. (1864), 93, 351. 

 ™This Journal (1906), 1, 1020. 



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