What is to be Done? 115
children and ten normal. Both of these are in accordance with Mendelian expectations.
We further find that in the cases where one parent was feeble-minded and the other undetermined, the children were nearly all feeble-minded, from which we might infer that the probabilities are great that the unknown parent was also feeble-minded.
We shall not go further into this matter in the present paper, but leave the detailed study of this family from the Mendelian standpoint for further consideration, when we take up the large amount of data which we have on the three hundred other families. Enough is here given to show the possibility that the Mendelian law applies to human heredity. If it does, then the necessity follows of our understanding the exact mental condition of the ancestors of any person upon whom we may propose to practice sterilization.
From all of this the one caution follows. At best, sterilization is not likely to be a final solution of this problem. We may, and indeed I believe I must, use it as a help, as something that will contribute toward the solution, until we get segregation thoroughly established. But in using it, we must realize that the first necessity is a careful study of the whole subject, to the end that we may know more both about the