408 THE CAUSES OF THE XI 
it is certainly a variation which carried with it no 
use or benefit; and yet you see the tendency to 
perpetuation may be so strong, that, notwithstand- 
ing 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 ? 
Réaumur narrates this case only as faras the third 
generation, Certainly it would have been an ex- 
ceedingly 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 sheep, which were 
very active and robust, would roam abroad, and 
without much difficulty jump over these fences in- 
to other people’s farms. As a matter of course, 
this exuberant activity on the part of the sheep 
constantly gave rise toall sorts of quarrels, bicker- 
