1.] ANTECEDENTS. 37
the second. It is a matter of great interest to compare with these figures the number of the children of the scientific men themselves. It is easy to do so with fairness, because the time of marriage proves to be nearly the same in both cases ; if anything, the scientific men marry earlier than their parents. It remains to eliminate all cases of absolutely sterile marriages on the part of the scientific men, and those in which there might yet be other children born. Having attended to these precautions, I find the number of their living children (say, of ages between 5 and 30) to be 4.7. This implies a diminution of fertility
as compared with that of their own parents, and confirms the common belief in the tendency to an extinction of the families of men who work hard with the brain. On the other band, I shall show that the health and energy of the scientific men are remarkably high ; it therefore seems strange that there should be a falling off in their offspring. I have tried in many ways to find characteristics common to those scientific men whose families were the smallest, but have only lighted upon one general result, which I give provisionally,
