148 THE WONDER OF LIFE 



out that they throve particularly well when artificially 

 introduced, as into Madeira, the Azores, and Mauritius, 

 * but as these animals and their spawn are immediately 

 killed (with the exception, as far as known, of one Indian 

 species) by sea- water, there would be great difficulty in 

 their transportal across the sea, and therefore we can see 

 why they do not exist on strictly oceanic islands '. They 

 could not be transported on trees and the like, as some 

 animals have been, without fatal drenching. Darwin 

 makes mention of an exception, and we have recently 

 (1911) had a circumstantial account by Mr. A. S. Pearse 

 of sea-shore frogs at Manila. He quotes Dr. Gadow's 

 words, ' Common salt is poison to the Amphibia ; even 

 a solution of 1 per cent, prevents the development of the 

 larvae ', and then reports that he saw little frogs of the 

 genus Rana hopping about on the flats of an estero, or tidal 

 creek, opening into Manila Bay. Two holes made by the 

 crab Sesarma bidens were seen to be full of wriggling tad- 

 poles newly hatched. Samples of water from a pool with 

 tadpoles on the edge of the creek were analysed, and it was 

 found that the tadpoles were developing in slightly diluted 

 sea-water, containing as much as 2 per cent, of sodium 

 chloride. It seems, then, that both tadpoles and frogs can 

 stand much more than a grain of salt. 



Audacity. There is sometimes what we may venture 

 to call sheer audacity in the things animals do and succeed 

 in doing. Taking such a serious matter as the disposal of 

 the eggs in birds, we find, of course, all manner of careful 

 nests and secure hiding-places and safe sites, but we also 

 find sheer audacity. We do not refer to the often reported 

 cases of birds nesting inside a hat, or up the sleeve of a 

 coat, or inside an unlit station-lamp ; for while a few of 



