69 ' 



CHAPTER IV. 



PAIRING OF BIRDS. 



IT would not be easy to select a more striking in- 

 stance of the wisdom displayed in regulating the 

 works of creation, than the extraordinary, and, to us 

 inexplicable, fact of the males and females of all ani- 

 mals being always found in nearly the same propor- 

 tional numbers. With respect to mankind, for 

 example, it has been proved by taking a census of 

 the population in different countries, that the ratio of 

 the two sexes shows very little variation. Hufeland 

 found that in Germany there are about twenty-one 

 males to twenty females*; by an average of 58,000 

 births at the Dublin Lying-in-Hospital the propor- 

 tion of males to females was found to be as ten to 

 nine t ; arid by the population returns for England 

 and Wales from 1811 to 1820, the number of males 

 born was 1,664,557, and of females, 1,590,510 1. 

 It has been inferred that the uniform excess of male 

 births is providentially designed to meet the greater 

 mortality arising from men being, by their habits of 

 life, more exposed to dangers. No physiological 

 investigation hitherto attempted has been successful 

 in elucidating the more immediate causes of these 

 wonderful facts, though some of the laws by which 

 they are regulated have recently been successfully 

 traced by the curious experiments of M. Girou de 



* Edin. Phil. Journ. iii. 296-9. 



t Cross, Med. Schools of Paris, p. 191. 



J Population Abstract, p. 154. 



