636 ME. A. H. CHURCH ON TURACIN, AN ANIMAL PIGMENT CONTAINING COPPER. 
difficult to perceive whence the Touracous derive the copper which their red feathers con- 
tain ; and I have actually succeeded in obtaining unmistakable indications of copper from 
the ash of three fruits of a plantain, the common Musa sapientum. There is, of course, 
still room for experiment and further observation in this direction. Researches as to 
the source of copper 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 captivity will doubtless lead to interesting results. The whole 
subject of the occurrence of copper in animal products is fraught with physiological as 
well as chemical interest. 
In conclusion I must express my obligation for the assistance afforded me, during the 
progress of the present inquiry, by those friends whose names I have already mentioned, 
and by others who have rendered me special aid. To Dr. J. H. Gladstone I am indebted 
for the drawings of spectra which accompany this paper ; to Philip Court, Esq., of Port 
Elizabeth, for an ample supply of Touracous when the stores of the London natural- 
history dealers were exhausted ; and, especially, to my assistant, Mr. B. J. Grosjean, for 
the laborious and conscientious care with which he has executed nearly the whole of the 
analytical work involved in the present research. 
