232 Tlic World-Evidence. 



they still " faithfully incubate their delicate sea-green 

 eggs." That is scientific exactitude with a ven- 

 geance. Caution run mad nearly enough, and leading 

 nearly enough to logical contradiction. The evidence 

 of Mr. Macllwraith, or Mr. Nuttall, of Mr. G. T. 

 Gentry, of Mr. J. L. Davidson, and not a few others, 

 was before Professor Newton in 1893, ^^'^ ^^^^ is all 

 the modification he will make. Surely it is not too 

 much to say that Professor Alfred Newton is more 

 concerned for his amour propre than for evidence; 

 and we are to bow down grovelling before his " au- 

 thority " in a case where facts — observed facts — must 

 alone decide it. 



Mr. Gentry, in his Birds of Pennsylvania, ii, p. 115, 

 remarks concerning the American cuckoo : 



" As the eggs are deposited at irregular intervals, 

 it happens that the same nest contains both eggs and 

 young birds, which seems to be a wise provision of 

 nature in strengthening that degree of warmth which 

 is denied by the shallowness and looseness of the 

 nest." 



Mr. Gentry has never known more than a single 

 brood in one season — a most important point in view 

 of the disposal by the majority of these cuckoos of 

 one half of their eggs. 



These facts are certainly not without their own 

 significance in view of our proposition. These birds, 

 in the words of Mr. Macllwraith, exhibit no love 

 for the brooding and rearing process as do most other 

 birds ; they are fain to limit the period of it — also the 

 number of young raised by themselves. They build 

 but a sorry make-shift of a nest, without sufficiency 

 of warmth. They, at least, have a strong tendency 



