2l6 THE HISTORY OF CREATION. 



this ram with normally shaped ewes, he produced a whole 

 race of sheep, all of which had the qualities of the father, 

 short and crooked legs and a long body. None of them 

 could leap across the hedges, and they therefore were much 

 liked and jDropagated in Massachusetts. 



A second law, which likewise belongs to the series of 

 progressive transmissions, may be called the law of estab- 

 lished or habitual transmission. It manifests itself in this, 

 that qualities acquired by an organism during its individual 

 life are the more certainly transmitted to its descendants 

 the longer the causes of that change have been in action, 

 and that this change becomes the more certainly the pro- 

 perty of all subsequent generations the longer the cause of 

 change acts upon these latter also. The quality newly 

 acquired by adaptation or mutation must be established 

 or constituted to a certain degree before we can cal- 

 culate with any probability that it will be transmitted 

 at all to the descendants. In this respect transmission re- 

 sembles adaptation. The longer a newly acquired quality 

 has been transmitted by inheritance, the more certainly 

 will it be preserved in future generations. If, therefore, 

 for example, a gardener by methodical treatment has pro- 

 duced a new kind of apple, he may calculate with the 

 greater certainty upon preserving the desired peculiarity 

 of this sort the longer he has transmitted the same by 

 inheritance. The same is clearly shown in the trans- 

 mission of diseases. The longer consumption or madness 

 has been hereditary in a family the deeper is the root of 

 the evil, and the more probable ib is that all succeeding 

 generations will suffer from it. 



We may conclude the consideration of the phenomena of 



