43^ comml:rcial description of of the Indian Islands make no distinction between the variety of swallow which affords the esculent nest and ariy other, nor do I believe that naturalists have remarked any. As an article of commerce, the quality of the nest is determined by several circumstances, as the nature and situation of the cave, its extent, but, above all, the time at which the nest is taken. The best nests are those obtained in deep damp caves, and such as are taken before the birds have laid their eggs. The coarsest are those obtained after the young have been fledged. The finest nests are the whitest, that is, those taken before the nest has been rendered impure by the food and feces of the young birds. The best are white, and the inferior dark-coloured, streaked with blood, or in- termixed with feathers. It may be remarked, how- ever, that some of the natives describe the purer nests as the dwelling of the cock-bird, and always so designate them in commerce. Birds' nests are collected twice a-year, and, if regularly collected, and no unusual injury be offered to the caverns, will produce very equally, the quantity being very little if at all improved by the caves being left altogether unmolested for a year or two. Some of the caverns are extremely difficult of access, and the nests can only be collected by persons accustomed from their youth to the office. The most remarkable and productive caves in Java,
