THE OVARIAN EGG. 291 



are, in fact, the component parts of the little Turtle 

 that is to be. They will undergo certain modi- 

 fications, to become flesh-cells, blood-cells, brain- 

 cells, and so on, adapting themselves to the dif- 

 ferent organs they are to build up ; but they have 

 as much their definite and appointed share in the 

 formation of the body now as at any later stage 

 of its existence. 



We are so accustomed to see life maintained 

 through a variety of complicated organs, that we 

 are apt to think this the only way in which it can 

 be manifested ; and, considering how entirely the 

 life of an adult animal is dependent upon the 

 organs through which it is sustained, it is natu- 

 ral that we should be deeply impressed by their 

 connection. But embryological investigations 

 have taught us that during the incipient growth 

 of the higher animals none of these organs exist, 

 and yet the principle of life is active, and even 

 after the organs are formed, they cannot act at 

 once, most of them being enclosed in the whole 

 structure, in a way which interferes with their 

 later functions. In the little Chicken, for in- 

 stance, before it is hatched, the lungs cannot 

 breathe, for they are surrounded by a fluid ; the 

 senses are inactive, for they receive no impres- 

 sions from without, and all those functions estab- 

 lishing its relations with the external world lie 

 dormant, for as yet they are not needed. But 



