Frank thought they had seen crows enough around Bangkok to supply the wants of the whole of Massachusetts. Evidently the inhabitants did not molest them, or they would not be as bold as he had found them.
"Then, too," the Doctor continued, "they have the sparrow, the same as in Europe and America, and the ornithologists say that Siam is the most southerly limit of this bird. As you go south in Asia, you will not find the sparrow anywhere else except where he has been introduced by the European inhabitants.
EDIBLE SWALLOWS NESTS.
"Some of the trade of Siam consists in shipping to China the edible portion of a bird's-nest, and this is the material from which the Chinese make their famous 'birds'-nest soup.' In Canton and Hong-kong it sells for its weight in silver, and sometimes is even dearer than that. It is found on the western coast of the Gulf of Siam, and also on the east coast of the Bay of Bengal; the bird makes his nest in caves among the rocks, and the work of collecting the nests is both difficult and dangerous."
"What kind of a bird is it?" Fred asked.
"It is a species of swallow," was the reply; "it is about as large as the common swallow with which you are familiar, and its movements through the air are much like those of the American bird; and in the same way that our swallows like to build in barns and chimneys, and other dark places, the Siamese one constructs his dwelling among the rocky caves along the coast."
"What is the peculiarity of the bird's-nest that the Chinese like so much?" one of the boys inquired.