COPPER.                                         429
	turns the workmen's hair grass-green. Curiously enough, with reference to some of the tropical birds, it is found that traces of copper serve a highly ornamental purpose in giving brilliant colouring to certain parts of their plumage. Thus, the brilliant red of the wing feathers of the turacos is due to a colouring matter derived from the banana, (or its twin brother, the plantain,) upon which these birds exclusively feed. But, none the less, the banana, cannot be regarded as a cosmetic, whether for birds, or for human beings. The coloured races who have hitherto been addicted to this fruit as a food do not exhibit any beauty of complexion ; moreover, the scarlet pigment which obtains in the wings of the turacos, as derived from bananas, being soluble in water, is apt to be washed out by a shower. Yet the banana is certainly a remarkably wholesome fruit for our eating and, perhaps so because of the trace of copper which it contains. A little iron is essential to healthy blood ; and a little copper may likewise subserve some useful end in the human economy, particularly as a potential bactericide. A few words as to the dietetic value of bananas will not be out of place here. Mr. Harold Crichton-Browne has written forcibly on this topic. He reminds us that the delicious fruit is a well-stocked source of real nutri­ment ; it supplies material for combustion, and thus for the maintenance of our animal heat; it also serves to build up the muscular systemj and to repair waste of nerve tissue. The flour made from dried bananas is equal in nutritive value to rice. (We have recently gained a practical lesson respecting the invigorating, and sustaining powers of rice, as demonstrated by the victorious achievements of the Japanese soldiers in the