THE RATE OF GROWTH 



121 



able to let you follow the growth of the chick a little 

 farther, and accordingly I present another picture 

 (Fig. 43), which shows an embryo of about ten days. 

 The little marks upon the surface of these embryos 



FIG. 43. A CHICK REMOVED FROM AN EGG WHICH HAD BEEN INCUBATED 

 10 DAYS AND 2 HOURS. Magnified four diameters. After Keibel. 



indicate the commencing formation of the feathers. 

 A comparison of the series of figures proves that the 

 development is taking place with marvellous speed. 

 We need only to look at these stages, comparing them 



