SIR HARRY JOHNSTON'S plea for the Plumage Bill in NATURE of December 11 will, no doubt, be considered an acceptable contribution by those who believe they possess the mental altitude to which he was born. I venture, however, to suggest that if he and his friends will leave their high mental estate and descend to the plain facts that business men must consider in this lower sphere, he will be obliged to admit that, like the trade, the educated naturalist has much to learn.