Clifton College Scientific Society. 39 



a deep brown tint, destroying it ; in oil of vitriol it is soluble, 

 but, in all probability, with partial alteration. Turacin seems 

 to have slightly acid properties ; though it dissolves very 

 freely in carbonated alkalies, caustic alkalies are still more 

 eifective. Turacin, by long exposure to air and moisture, or 

 by continued ebullition with water or alkaline liquids, ac- 

 quires a colour closely resembling that of chlorophyll. 



' Composition of Turacin. — The volatile constituents of 

 Turacin are carbon, hydrogen, nitrogen, and oxygen, in what 

 proportions I shall presently state. It contains no sulphur. 

 The ash, or non-volatile constituents of the new pigment 

 have also been submitted to a careful examination. Turacin 

 may be dried at 100° without change ; but at a considerably 

 higher temperature its surface colour alters, becoming bluish 

 and then a dull green. Afterwards it shows some symptoms 

 of fusion, giving off a violet vapour resembling that of 

 iodine ; it finally burns away, leaving a greyish black ash. 



' The close resemblance of Turacin to Cruorin induced me 

 to test at once — m the ash of the new colouring matter — for 

 iron, the characteristic metallic constituent of the pigment 

 of the blood, and of its derivatives. The ash of Turacin was 

 dissolved in nitric acid, excess of sodic acetate added, and 

 then potassic ferrocyanide. Much to my surprise, instead of 

 the deep blue ferric ferrocyanide, a copious piu'ple brown 

 precipitate of cupric ferrocyanide made its appearance. Not 

 only was copper preseiit, but there was so much of it, that it 

 could be detected by its spectrum, when the ash of a few red 

 barbs of the original feathers was moistened with strong 

 hydrochloric acid and exposed on a platinum wire to the 

 flame of a Biinsen burner. 



' This detection of copper in the colouring matter was so 

 extraordinary, that it became necessary to sift the matter 

 thoroughly. The idea that a preservative solution contain- 

 ing copper had been used in dressing the skins of the bird 

 suggested itself; but this notion was soon proved untenable ; 

 for there is no copper in any part of the skin save in the red 

 feathers, and in these feathers themselves the presence of 

 copper is strictly confined to the red barbs. Even barbs 

 that are partly red and partly black contain no copper in 

 their black parts, and abundance in those that are red. 

 Moreover, as acids do not wash out the copper from the 

 feathers, and the most severe chemical treatment, short of 

 actual destruction of the pigment itself, does not remove it 

 from the prepared and pure Turacin, it is evident that this 

 metal, copper, is an integral constituent of the substance 



