140 Analyses of Books. [Feb. 



Article XIV. 



Analyses of Books. 

 Philosophical Transactions for the Year 1817, Part II. 



(Concluded from p. 58.) 



It has been long known that the Island of Java contains a pecu- 

 liar species of swallow, the nest of which is composed of an animal 

 substance ; but naturalists have never been able to ascertain the 

 source from which it is derived, nor the materials of which it is 

 formed. Several circumstances, however, seemed to prove that 

 it proceeded from the stomach of the animal itself; and this 

 induced Sir Everard Home to examine the digestive organs of 

 this peculiar kind of swallow, and to compare them with those of 

 other species of the same genus. The author was informed by 

 Sir Stamford Raffles, late Governor of Java, that the swallows, 

 peculiar to that island, do not migrate ; they spend a consider- 

 able pail of the day in the neighbourhood of extensive swamps, 

 that abound with various kinds of insects, and retire, at the close 

 of the day, to large caverns, which they inhabit in prodigious 

 numbers. The bird is double the size of our common swallow \ 

 the male and female lie in separate nests, each adapted to their 

 form, the female nest being wider and deeper, in order to receive 

 the eggs. 



By comparing together the gastric glands of the Java swallow, 

 the common swallow, and the black-bird, the peculiar structure 

 of the first was sufficiently obvious. According to the descrip- 

 tion, " there is a membranous tube surrounding the duct of each 

 of the gastric glands, which, after projecting into the gullet for 

 a little way, splits into separate portions like the petals of a 

 flower." In the examination of the parts, the author received 

 the assistance of Mr. Bauer, who has given us exact repre- 

 sentations of what he detected by his microscope. It is reason- 

 able to conclude that these peculiarly formed tubes secrete the 

 animal matter of which the nests are composed, although we 

 have no means of judging how the process is conducted. 



This provision, which the Java swallow possesses, of forming 

 a nest from its own secretions, is a remarkable anomaly among 

 the higher order of animals ; it is said by the author to prove 

 that this bird was intended by nature to be an inhabitant of the 

 island of Java, " in which nothing is to be met with out of which 

 a nest could be constructed ; " but we are not informed in 

 what this deficiency of materials consists, or upon what it 

 depends. Mr. Brande examined the substance, and found it to 

 have " properties intermediate between gelatine and albumen ; " 

 the quantity of gelatine, however, appears to be very minute, so 



