32G EDIBLE BIRDS' NESTS. 



men assured Ksempfer that tlieir nests were composed of the flesh 

 of the great poulpe. A more probable explanation, however, was 

 found by Rumphius in the occurrence on the sea-coasts of a soft 

 almost cartilaginous plant which he with confidence asserted was the 

 material from which these swiftlets constructed their nests; but 

 subsequently this naturalist inclined to the opinion that the sub- 

 stance of which the edible birds' nests are composed is merely a 

 secretionary product. In these two views of Rumphius we have 

 the two sides of the controver.sy very much as it at present stand.s. 

 On the one hand, there are those who hold that this substance is a 

 secretionary product : on the other hand, the opinion is held that the 

 nest is constructed of a vegetable matter, usually resulting from the 

 growth of a microscopic alga, which is found in the caves and on the 

 faces of the cliffs where the nests occur. All the weight of experi- 

 ment and of actual observation tends to negative the view of the 

 ves^etable orimn of this substance. Sir Everard Home in I8l7 de- 

 clared his opinion that certain peculiar gastric glands, which he 

 found in one of these birds, secreted the mucus of which the nest 

 was formed. In 1859, Dr. Bernstein,^ after having carefully studied 

 the habits of the birds in ^[uestion, came to the conclusion that their 

 nests are formed from the secretion of certain salivary glands which 

 are abnormally developed during the nest-building season. M. 

 Trecul, who held the same opinion, showed that the bird eonstruc':s 

 its nest by means of a mucus which flows abundantly from its beat 

 at the pairing time.^ This last view is strongly supported by Mr. 

 Layard, wlio unhesitatingl}^ pronounces his opinion that these 

 swiftlets build their nests from the secretionary products of their 

 own salivary glands.^ However, when Mr. Pryer v^isited in March, 

 1884. the birds' nest caves in British North Borneo, he considei'ed 

 that he had found the source of the material of which the nests were 

 composed in the occurrence of a " fungoid growth," which incrusted 

 the rock in damp places, and which, when fresh, resembled half- 

 melted gum ti'agacanth. Without at present expressing an opinion 

 opinion as to the validity of the inference Mr. Pryer drew from his 

 observations in these caves, I may observe that the " fungoid growth" 

 has been determined by^Mr. George Murray,^ of the Botanical 

 Department of the British Museum, to be the result of the growth 



iJourn. fur Ornithologie, 1859, pp. 112-115; also Proceed. Zoolog. Soc, 1885, p. 610. 



2 "A General System of Eotany," by Le Maout and Decaisne : London, 1873, p. 983. 



3 " Nature," Nov. 27th, 1884. ' 

 •«Proc. Zoolog. Soc, 1884: p. 532. 



