FERTILIZATION 63 



union. When they unite there is only one individual where 

 there were two before. This is just the opposite of 

 reproduction, which gives two individuals where there 

 was only one before. But this new individual has powers 

 of development which neither of the cells that entered 

 into it had. Instead of being feeble, as these two cells 

 were, it is completely renewed. It has youth and the 

 power to grow into an adult of the species to which it 

 belongs. 



A fertilized egg, then, is the result of a union of two 

 individuals from different sources. Each adult is not one 

 offspring merely. It is a composite made up of two 

 offspring, a male and a female. 



6. Fertilization and "Blood." We have a saying that 

 "blood will tell," and we mean by it that good or bad 

 qualities in the parents are sure in the long run to crop 

 out in their descendants. The reasons for this always 

 interest us. This wonderful process of fertilization throws 

 some light on the fact of inheritance. We know that 

 everything that is actually inherited, in the biological 

 sense, comes by way of these sex cells. To be sure, 

 parents can influence and change their offspring in other 

 ways than this, but such influence is not inheritance. 



Now if this is true, we can make some valuable 

 conclusions from what we have. All the protoplasm 

 outside the nucleus came from the mother; the matter 

 in the nucleus, and only that, came equally from both 

 parents. But so far as we can see, in the long run, 

 offspring are no more liable to be like the mother than 

 like the father. These facts show pretty conclusively 

 that those qualities in which the parents are unlike are 

 carried somehow by the nuclei, because only the nuclei 

 come equally from both parents. It is clear that likeness 

 to one parent or the other is not determined by bulk of 

 protoplasm; otherwise the female characteristics would 

 be much more likely to be transmitted than those of the 



