HEREDITARY VARIATION 75 



notice of them to preserve their skeletons ; and although 

 Colonel Humphreys states that he sent a skeleton to the 

 president of the Royal Society at the same time that he 

 forwarded his paper, I am afraid that the variety has 

 entirely disappeared ; for a short time after these sheep 

 had become prevalent in that district, the Merino sheep 

 were introduced ; and as their wool was much more valu- 

 able, and as they were a quiet race of sheep, and showed 

 no tendency to trespass or jump over fences, the Otter 

 breed of sheep, the wool of which was inferior to that of 

 the Merino, was gradually allowed to die out. 



You see that these facts illustrate perfectly well what 

 may be done if you take care to breed from stocks that 

 are similar to each other. After having got a variation, if, 

 by crossing a variation with the original stock, you multiply 

 that variation, and then take care to keep that variation 

 distinct from the original stock, and make them breed 

 together, then you may almost certainly produce a race 

 whose tendency to continue the variation is exceedingly 

 strong. 



This is what is called " selection " ; and it is by exactly 

 the same process as that by which Seth Wright bred his 

 Ancon sheep, that our breeds of cattle, dogs, and fowls, 

 are obtained. There are some possibilities of exception, 

 but still, speaking broadly, I may say that this is the way 

 in which all our varied races of domestic animals have 

 arisen ; and you must understand that it is not one 

 peculiarity or one characteristic alone in which animals may 

 vary. There is not a single peculiarity or characteristic 

 of any kind, bodily or mental, in which offspring may 

 not vary to a certain extent from the parent and other 

 animals. 



Among ourselves this is well known. The simplest 

 physical peculiarity is mostly reproduced. I know a case of 

 a man whose wife has the lobe of one of her ears a little 

 flattened. An ordinary observer might scarcely notice it, 

 and yet every one of her children has an approximation 

 to the same peculiarity to some extent. If you look at 

 the other extreme, too, the gravest diseases, such as gout, 

 scrofula, and consumption, may be handed down with 

 just the same certainty and persistence as we noticed in 

 the perpetuation of the bandy legs of the Ancon sheep. 



However, these facts are best illustrated in animals, and 

 the extent of the variation, as is well known, is very re- 



