278 THE INDUCTIONS OF BIOLOGY. 



When produced by gamogenesis, the new individuals be- 

 come (in a morphological sense) independent of the parents 

 while still in the shape of centres of development, rather than 

 axes of development; and this even where the reverse is 

 apparently the case. The fertilized germs of those inferior 

 plants which are central, or multicentral, in their develop- 

 ment, are of course thrown off as centres; and the same is 

 usually the case even in those which are uniaxial or multi- 

 aiiaL In the higher plants, of the two elements that go to 

 the formation of the fertilized germ, the pollen-cell is abso- 

 lutely separated from the parent-plant under the shape of a 

 centre, and the egg-cell, though not absolutely separated from 

 the parent, is still no longer subordinate to the organizing 

 forces of the parent. So that when, after the egg-cell has 

 been fertilized by matter from the pollen-tube, the develop- 

 ment commences, it proceeds without parental control: the 

 new individual, though remaining physically united with 

 the old individual, becomes structurally and functionally 

 separate: the old individual doing no more than supply 

 materials. Throughout the animal kingdom, the new 



individuals produced by gamogenesis are obviously separated 

 in the shape of centres of development wherever the repro- 

 duction is oviparous: the only conspicuous variation being 

 in the quantity of nutritive matter bequeathed by the parent 

 at the time of separation. And though, where the reproduc- 

 tion is viviparous, the process appears to be different, and 

 in one sense is so, yet, intrinsically, it is the same. For in 

 these cases the new individual really detaches itself from the 

 parent while still only a centre of development ; but instead 

 of being finally cast off in this state it is re-attached, and 

 supplied with nutriment until it assumes a more or less com- 

 plete axial structure. 



| 77. As we have lately seen, the essential act in gamo- 

 genesis is the union of two cell-nuclei, produced in the great 

 majority of cases by different parent organisms. Nearly 



