292 THE OVARIAN EGG. 



the organs are there, though, as we have seen in 

 the Turtle's egg, they were not there at the be- 

 ginning. How, then, are they formed? We 

 may answer, that the first function of every or- 

 gan is to make itself. The building material is, 

 as it were, provided by the process which divides 

 the yolk into innumerable cells, and by the grad- 

 ual assimilation and modification of this material 

 the organs arise. Before the lungs breathe, they 

 make themselves ; before the stomach digests, it 

 makes itself; before the organs of the senses act, 

 they make themselves ; before the brain thinks, 

 it makes itself. In a word, before the whole 

 system works, it makes itself out of the elements 

 given by the formation of independent eggs : its 

 first office is self-structure. 



At the period described above, however, when 

 the new generations of cells are just set free and 

 have taken their place in the region where the 

 new being is to develop, nothing is to be seen of 

 the animal whose life -is beginning there, except 

 the filmy disk lying on the surface of the yolk. 

 Next come the layers of white or albumen around 

 the egg, and last the shell which is formed from 

 the lime in the albumen. There is always more 

 or less of lime in albumen, and the hardening of 

 the last layer of white into shell is owing only to 

 the greater proportion of lime in its substance. 

 In the layer next to the shell there is enough of 



