HEREDITARY TRANSMISSION AND VARIATION. 97 



case a further development of that abnormal type. 

 You see it is only in the fourth, in the person of 

 Marie, that the tendency, when it appears but slightly 

 in the second generation, is washed out in the third, 

 while the progeny of Andre, who escaped in the first 

 instance, escape altogether. 



We have in this case a good example of nature's 

 tendency to the perpetuation of a variation. Here it 

 is certainly a variation which carried with it no use 

 or benefit ; and yet you see the tendency to perpetua- 

 tion may be so strong, that, notwithstanding a great 

 admixture of pure blood, the variety continues itself 

 up to the third generation, which is largely marked 

 with it. In this case, as I have said, there was no 

 means of the second generation intermarrying with any 

 but five-fingered persons, and the question naturally 

 suggests itself, What would have been the result of such 

 marriage ? Reaumur narrates this case only as far as 

 the third generation. Certainly it would have been an 

 exceedingly curious thing if we could have traced this 

 matter any further; had the cousins intermarried, a 

 six-fingered variety of the human race might have 

 been set up. 



To show you that this supposition is by no means an 

 unreasonable one, let me now point out what took place 

 in the case of Seth Wright's sheep, where it happened 

 to be a matter of moment to him to obtain a breed 

 or raise a flock of sheep like that accidental variety 

 that I have described — and I will tell you why. In 

 that part of Massachusetts where Seth Wright was 

 living, the fields were separated by fences, and the 



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