Some writers, objecting altogether to stimulating narcotics, assert that the use of coca produces all the evil results of opium; but this, from the evidence of many enlightened travellers, seems not to be the case. Taken immoderately, no doubt it is injurious,--as is tea, coffee, tobacco, or wine; but used as it generally is by the natives, it is to them a great blessing. The valleys, however, most suitable for its cultivation are reputed to be unhealthy. So valuable was coca considered in the days of the Incas, that divine honours were paid to it, and it was especially the property of the sovereign. Even at the present day the miners of Peru throw a quid of coca against the hard veins of ore, under the belief that they are thereby more easily worked. The natives also sometimes put coca in the mouth of the dying man, believing that if he can taste the fragrant leaf it is a sure sign of his future happiness. Its moderate use is considered wholesome; and European travellers who have chewed coca state that they could thus endure long abstinence from food without inconvenience, and that it enabled them to ascend precipitous mountainsides with a feeling of lightness and elasticity, and without losing breath. PART THREE, CHAPTER TEN. HUMMING-BIRDS (TROCHILIDAE) OF THE CORDILLERAS AND WESTERN COAST. We should scarcely have expected to find the smallest specimens of the feathered tribe inhabiting the same region as the mighty, coarse-feeding condor; but whereas the latter pounces down on his carrion banquet into the plains below, the little humming-bird seeks his food from the bright flowers which clothe the mountainside, or the minute insects which fly amid them. Humming-birds are found throughout the whole of the New World, from the borders of the great Canadian lakes, along the entire range of the Cordilleras, down to the shores of Tierra del Fuego; also in the West India Islands, and over the whole wide-extending plains watered by the Orinoco, the Amazon, and other great rivers which empty themselves into the Atlantic. The greater number of the species exist about the equator, and, as might be expected, diminish as we proceed either to the south or north. They obtain their name on account of the humming sound which their wings produce when they are hovering over the flowers in which they seek their food. The sound, however, varies in the species; and the well-practised ear of the naturalist is often able to distinguish without difficulty one from the other. Some are furnished with strong wings, with which they can extend their flight over a large extent of country; and many are migratory. Others again have only small wings, and are compelled to remain always in the same locality. So rapid is their flight, that the eye can scarcely distinguish the little bird as it cleaves the air; and when hovering over a flower, the wings appear like filmy grey fans on either side.