SIR ARTHUR H. CHURCH ON TURACIN. 643 



spectrum of an alkaline solution of turacin are not unlike those 

 of CO -haemoglobin. However, the absorption-spectrum of tiu-acin 

 is sufficiently characteristic to enable one to use it as a criterion 

 of the presence of this pigment in the red feathers of birds. So 

 when Dr. C F. W. Krukenberg announced the occurrence of 

 turacin in a species not belonging to the Musophagidae, and not 

 even African, it became necessary to test the assertion. The bird 

 in question is a Cuckoo from the Philippines, Dasylophus super- 

 ciliosus. I obtained a skin, then an assurance of identity from 

 the Bird Department of the British Museum. I removed the 

 sparse red feathers from the head of this Cuckoo and submitted 

 them to spectroscopic scrutiny. They did show an absorption- 

 band, but it was situated midway between the two bands of 

 turacin. Moreover, the colouring-matter, which is orange-red, not 

 crimson, cannot be extracted by ammonia and contains no copper. 

 Hitherto, therefore, turacin has not been found to occur outside 

 the Musophagidaj. It is right to mention here that Dr. Kruken- 

 berg's statement as to its occurrence in a Dasylophus was made in 

 consequence of a report addressed to him at his request by the 

 authorities of the Senckenberg Museum in Frankfurt, and was 

 not the result of an experiment made by himself*. It has 

 unfortunately found its way into various articles and books, e. g. 

 Enc. Brit. x. p. 226 a, where we read " But turacin is not, as was 

 supposed, confined to the feathers of the Plantain-eaters, since it 

 has been obtained from a Cuckoo, Dasylophus super ciliosus.^' I 

 have been able to secure a thi-eefold disproof of this statement, 

 for although the occurrence of this pigment in any bird other than 

 a Plantain-eater seemed unlikely, the closely-allied Cuckoos might 

 have supplied an instance. 



The occurrence of so large a percentage of copper as 7 in 

 isolated turacin needs a word of comment. It does not imply a 

 large amount of this metal in the plumage of a single bird ; a 

 high estimate gives less than -14 of a grain of the metal. And it 

 must be remembered that many recent analyses of vegetable 

 and animal matters show the wide distribution of copper in both 

 kingdoms. Two of the latest researches in this direction were 

 made by Mr. J. W. Dougalf in 1911 and by M. B. Guerithault 

 in 1912 J. In fact, there is no difficulty in accounting for the 

 presence of copper in Turacoes and for its amount. 



I purposely exclude from the present paper any discussion of 

 the curious green pigment named turacoverdin by Krukenberg ; 

 of the relationships between htematoporphyrin and the turaco- 

 porphyrin obtained from turacin by the action of acids ; and of 

 the supposed synthesis of turacin by treating hfematoporphyrin 

 with an ammoniacal copper solution. 



* C. F. W. Krukenberg, Vergleichend-Physiologische Vortrage C1886), Bd. i. 

 p. 152. 



t Pharm. .T. 1911 (4) xxxii. pp. 405-7. 



+ Bull. Sci. Pharmacol. 1912, xviii. pp. 633-639. 



Proc Zool. Soc— 1913. Ko. XLIII. 43 



