Clifton College Scientific Society. 41 



Copper Cruorin. Moreover, Turacin does not seem to occur 

 ill corpuscles, but to be homogeneously distributed in the 

 barbs, barbules, and crochets of the red feathers in which 

 it occurs. 



' Turacin seems to characterise the closely-allied genera 

 Musopharja and Corythaix. These birds, though with the 

 other Touracous distinctive of the African Ornis, are not 

 common ; and in consequence, the supply of Turacin for ex- 

 perimental pui-poses is very limited. 1 have not detected it 

 in any of the other red-plumaged birds, which I have 

 examined. The quantity of Turacin in a single bird is small. 

 It is most abundant at the pairing season, and the bridal 

 plumage of a Corythaix cdbocristata generally yields from two 

 to three gTains of the pigment. One bird may then contain 

 in the colouring matter of its wings nearly '2 of a grain of 

 metallic copper. 



' Turacin is the first animal or vegetable pigment contain- 

 ing copper as an essential constituent, which has hitherto 

 been isolated ; yet traces of copper have been repeatedly 

 found in both animals and plants. It was detected by 

 Harlen in the blood of certain Ascidia and Cephalopoda. It 

 occurs in Limulus cyclops, Cancer pagurus, Acantliias zeus, and 

 Conger vulgaris, its quantity being in inverse ratio to the 

 quantity of iron present. The blood of Helix pomaiia con- 

 tains much copper, the part of the ash insoluble in water 

 yielding 2*57 per cent. Many chemists have detected minute 

 traces of copper in human blood ; and twenty years ago 

 Deschamps arrived at the conclusion, that it is normally 

 contained in the blood of man and animals. Odliiig and 

 Dupre have indeed, subsequently, detected copper in flour, 

 straw, hay, meat, cheese and other articles of food. It has 

 been supposed that the copper detected in some of these 

 substances has been introduced in the course of analysis by 

 the use of brass burners, and retort rings ; but these in most 

 cases are a purely imaginary source of error. It is not 

 difficult to perceive, whence the Touracous derive the copper 

 which their feathers contain, and I have actually succeeded in 

 obtaining unmistakeable indications of copper from the ash of 

 thi'ee fruits of a plantain, the commonMusa sapientum. There 

 is, of course, still room for experiment and further observation 

 in this direction. Researches as to the source of cojDper — 

 whence vegetables assimilate it — the occurrence of ores of 

 copper near the habitats of the Touracous — and its detection 

 in the articles of food supplied to these birds, when kept in 

 cuj)tivity, will doubtless lead to interesting results. The 



