100 THE ARCHITECTURE OF BIRDS. 



that the nest is a material elaborated from the food 

 of the bird, a conjecture which would be proved, if, 

 on a skilful dissection, it were discovered that the 

 bird has any peculiar organs destined to perform 

 such a process."* 



" In the Java swallow," says Sir Everard Home, 

 " we have a structure of a particular nature ; there 

 is a membranous tube surrounding the duct of each 

 of the gastric glands, which, after projecting into the 

 gullet a little way, splits into separate portions like 

 the petals of a flower. That the mucus of which 

 the nest is composed is secreted from the surface of 

 these membranous tubes, there is no more doubt 

 than that the gastric juice is secreted from the glands 

 whose ducts these tubes surround. For what pur- 

 pose so extraordinary an apparatus could be provi- 

 ded would probably have puzzled the weak intellects 

 of human beings, and given rise to many wild theo- 

 ries, had not the animal matter of which the bird's 

 nest is composed, and the accurate observation of 

 Sir Stamford Raffles, led to the discovery of its use." 



Notwithstanding this apparently conclusive in- 

 vestigation, however, we cannot avoid giving the 

 opinion of Dr. Fleming, who says that, " though the 

 use of these lobes may puzzle, we cannot admit that 

 there is a shadow of proof, even from analogy, to 

 conclude that these secrete the materials of the 

 nest.*" 



It may give some solution to this discrepance to 

 mention that M. Lamouroux says positively there 

 are three species, of which the smallest makes the 

 most valuable nest. He is farther decidedly of opin- 

 ion, that the white nests of the smallest species are 

 chiefly composed of seaplants belonging to his Ge- 

 lidia, the second division of his Thalassiophytes, 

 which, by boiling or maceration, can be almost whol- 

 ly reduced to a gelatinous substance. The larger 



* History of the Indian Archipelago, vol. iii., p. 432. 

 f Philosophy of Zoology, vol. ii., p. 238, note. 



