286 THE OVARIAN EGG. 



the senses, between the organs of instinct and 

 sensation and those of mere animal functions. 

 At that stage of its existence, however, when 

 the egg consists of an outer sac, an inner sac, 

 and a dot, its resemblance to a cell is unmis- 

 takable ; and, in fact, an egg, when forming, is 

 nothing but a single cell. This comparison is 

 important, because there are both animals and 

 plants which, during their whole existence, con- 

 sist of a single organic cell, while others are 

 made up of countless millions of such cells. Be- 

 tween these two extremes we have all degrees, 

 from the innumerable cells that build up the 

 body of the highest Vertebrate to the single- 

 celled Worm, and from the myriad cells of the 

 Oak to the single-celled Alga. 



But while we recognize the identity of cell- 

 structure and egg-structure at this point in the 

 history of the egg, we must not forget the great 

 distinction between them, namely, that while 

 the cells remain component parts of the whole 

 body, the egg separates itself, and assumes a dis- 

 tinct individual existence. Even now, while still 

 microscopically small, its individuality begins. 

 Other substances collect around it, are absorbed 

 into it, nourish it, serve it. Every being is a 

 centre about which many other things cluster 

 and converge, and which has the power to assimi- 

 late to itself the necessary elements of its life. 



