188 NATURAL INHERITANCE. [chap. 



ance. Now we have seen that the personal heritage 

 from either Parent is one quarter, therefore as the total 

 heritage is one half, it follows that the Latent Elements 

 must follow the same law of inheritance as the Personal 

 ones. In other words, either Parent must contribute 

 on the average only one quarter of the Latent 

 Elements, the .remainder of them dropping out and 

 their breed becoming absolutely extinguished. 



There seems to be much confusion in current ideas 

 about the extent to which ancestral qualities are 

 transmitted, supposing that what occurs occasionally 

 must occur invariably. If a maternal grandparent be 

 found to contribute some particular quality in one 

 case, and a paternal grandparent in another, it seems 

 to be argued that both contribute elements in every 

 case. This is not a fair inference, as will be seen by 

 the following illustration. A pack of playing cards 

 consists, as we know, of 13 cards of each sort — hearts, 

 diamonds, spades, and clubs. Let these be shuffled 

 together and a batch of 13 cards dealt out from them, 

 forming the deal, No. 1. There is not a single card 

 in the entire pack that may not appear in these 13, 

 but assuredly they do not all appear. Again, let the 

 13 cards derived from the above pack, which we will 

 suppose to have green backs, be shuffled with another 

 13 similarly obtained from a pack with blue backs, 

 and that a deal, No. 2, of 13 cards be made from the 

 combined batches. The result will be of the same kind 

 as before. Any card of either of the two original 

 packs may be found in the deal, No. 2, but certainly 



