238 PHILOSOPHY OF ZOOLOGY. 



of Britain, have long been admired for the materials and 

 arrangement of their construction. But the edible nests of 

 the H. cscnlenta, a species found in the Indian Archipelago, 

 are still more remarkable. They form an article of trade 

 to the China market, where those of the first quality fetch 

 their weight in gold. They are employed to make soup, 

 to which is ascribed powerfully restorative qualities. The 

 substance of which these nests consists, has much the ap- 

 pearance of isinglass, and is disposed in irregular transverse 

 threads, with a, few feathers interposed. Neither the ana- 

 lytical experiments of Dobebeiner, nor those of Brande, 

 demonstrate it to be of animal origin *. The relatively 

 small portion of ammonia, indeed, which it yields, and its 

 facihty of incineration, rather lead to the conclusion, that 

 it is a vegetable gum. It was once supposed to be procured 

 from the scum of the sea. Those individual?, however, re- 

 siding fifty miles from the sea, employ the same materials as 

 those which dwell on the shore. The other species in those 

 districts, likewise employ a portion of the same substance 

 in the fabrication of their nests. It is much to be regret- 

 ted, that the recent historians of these regions have added 

 .so little to the history of tliis singular substance. 



Nostrils tubular. 



57. Caprimulgus. Goatsucker. The species of this 

 senus m\e indications of several characters for subdivision. 



• Sir EvERARD Home, (Phil. Trans. 1817, p. 332.) having found the 

 margin of the orifice of the gastric glands of the H. esculenta divided into 

 lobes, — a form he had not observed in other birds, — concluded that the sub- 

 stance of the nest was secreted by these lobes. Though the use of these 

 lobes may puzzle (to use the author's own words), " the weak intellects of 

 human beings," and give rise to " many wild theories," we cannot admit 

 that there is a shadow of proof, not even from analogy, to conclude that 

 these secrete the materials of the nest. The reasoning, indeed, which is cm- 

 ployed to support this '» wild theory," derived from the supposed history 

 of the bird, is at variance with the statements of Sir Thomas S. Raffles 

 and Mr Craxvford. 



