46 Professor A. E. Church [Feb. 17, 



copper being normally and invariably present by applying a few easy 

 tests and by the expenditure of half-a-crown in acquiring a touraco 

 wing. My results were, however, confirmed (in 1872) by several 

 independent observers, including Mr. W. Crookes, Dr. Gladstone, 

 and Mr. Greville Williams. And in 1873 Mr. Henry Bassett, at the 

 request of the late Mr. J. J. Monteiro, pushed the inquiry somewhat 

 further. I quote from Monteiro's ' Angola and the River Congo,' 

 published in 1875 (vol. ii. pp. 75-77). " I purchased a large bunch 

 of the red wing-feathers in the market at Sierra Leone, with which 

 Mr. H. Bassett has verified Professor Church's results conclusively," 

 &c, &c. Mr. Bassett's results were published in the Chemical News 

 in 1873, three years after the appearance of my research in the Phil. 

 Trans. As concentrated hydrochloric acid removes no copper from 

 turacin, even on boiling, the metal present could not have been a 

 mere casual impurity ; as the proportion is constant in the turacin 

 obtained from different species of touraco, the existence of a single 

 definite compound is indicated. The presence of traces of copper in 

 a very large number of plants as well as of animals has been incon- 

 testably established. And, as I pointed out in 1868, copper can be 

 readily detected in the ash of banana fruits, the favourite food of 

 several species of the " turacin-bearers." The feathers of a single 

 bird contain on the average two grains of turacin, corresponding to * 14 

 of a grain of metallic copper ; or, putting the amount of pigment 

 present at its highest, just one-fifth of a grain. This is not a large 

 amount to be furnished by its food to one of these birds once annually 

 during the season of renewal of its feathers. I am bound, however, 

 to say that in the blood and tissues of one of these birds, which I 

 analysed immediately after death, I could not detect more than faint 

 traces of copper. The particular specimen examined was in full 

 plumage ; I conclude that the copper in its food, not being then 

 wanted, was not assimilated. 



Let us now look a little more closely at these curious birds them- 

 selves. Their nearest allies are the cuckoos, with which they were 

 formerly united by systematists. It has, however, been long con- 

 ceded that they constitute a family of equal rank with the Cuculidae. 

 According to the classification adopted in the Natural History 

 Museum, the order Picariae contains eight sub-orders, the last of 

 which, the Coccyges, consists of two families, the Cuculidae and the 

 Musophagidae. To the same order belong the Hoopoes, the Trogons, 

 the Wood-peckers. The plantain-eaters or Musophagidae are 

 arranged in six genera and comprise 25 species. In three genera — 

 Turacus, Gallirex, and Musophaga — comprising eighteen species, and 

 following one another in zoological sequence, turacin occurs ; from 

 three genera (seven species) — Corythaeola, Schizorhis, and Gymno- 

 schizorhis — the pigment is absent. [The coloured illustrations to 

 H. Schlegel's Monograph (Amsterdam, 1860) on the Musophagidae 

 were exhibited]. The family is confined to Africa : 8 of the turacin- 

 bearers are found in the west sub-region, 1 in the south-west, 2 in 



