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