[End of February, 1868] I am in the second volume of your book, and I have been astonished at the immense number of interesting facts you have brought together.

I read the chapter on pangenesis first, for I could not wait.

I can hardly tell you how much I admire it.

It is a positive comfort to me to have any feasible explanation of a difficulty that has always been haunting me, and I shall never be able to give it up till a better one supplies its place,--and that I think hardly possible.

You have now fairly beaten Spencer on his own ground, for he really offered no solution of the difficulties of the problem.