147 



CHAPTER IX, 



EVOLUTION OF THE CHICK, 



IT has long been a favourite occupation with philo- 

 sophical naturalists, to observe the changes which an 

 ego- undergoes in hatching, from the first day that 

 the mother sits upon it till the chick breaks through 

 the prison- walls of the shell and emerges into open 

 day. The chief writers who have attended to the 

 various stages of this curious and interesting pro- 

 gress, are Fabricius d'Aquapendente, Harvey, Mal- 

 pighi, Maitre-Jean, Reaumur, Haller, Scarpa, Mec- 

 kel, Blumenbach, Front, Dutrochet, and SirE. Home. 

 The statements of these different inquirers we shall 

 now compare and condense. 



An Egg as it appears twelve hours after incubation, with a magnified view 



of the Embryo Chick. 



(This and the following cuts, which illustrate the changes in the egg, 

 are copied, by permission, from Sir E. Home's Comparative Anatomy.) 



