OCR Rendition - approximate

138 WATSON and GALTON.-Extinction of Families. Mr. Galton then read the following paper by the Rev. H. W. Watson and himself: On the PROBABILITY of the EXTINCTION of FAMILIES. By the Rev. H. W. WATSON. With PREFATORY REMARKS, by FRANCIS GALTON, F.R.S. THE decay of the families of men who occupied conspicuous po sitions in past times has been a subject of frequent remark, and has given rise to various conjectures. It is not only the families of men of genius or those of the aristocracy who tend to perish, but it is those of all with whom history deals, in any way, even of such men as the burgesses of towns, concerning whom Mr. Doubleday has inquired and written. The instances are very numerous in which surnames that were once common have since become scarce or have wholly disappeared. The tendency is universal, and, in explanation of it, the conclusion has been hastily drawn that a rise in physical comfort and intellectual capacity is necessarily accompanied by diminution in "fertility" -using that phrase in its widest sense and reckoning abstinence from marriage as sterility. if that conclusion be true, our population is chiefly maintained though the "proletariat," and thus, a large element of degradation is inseparably connected with those other elements which tend to ameliorate the race. On the other hand, M. Alphonse De Candolle has directed attention to the fact that, by the ordinary law of chances, a large proportion of families are continually dying out, and it evidently follows that, until we knowwhat that proportion is, we cannot estimatewhether any observed diminution of surnames among the families whose history we can trace, is or is not a sign of their diminished "fer tility." I give extracts from M. De Candolle's work in a foot-note,* and may add that, although I have not hitherto published anything on the matter, I took considerable pains some years ago to obtain numerical results in respect to this very problem. I made certain very simple, but not very inaccurate, suppositions, concerning average fertility, and I worked to the nearest integer, starting with 10,000 persons, but the computation became intolerably tedious after a few steps, and I had to abandon it. More recently, having first privately applied in vain to some * '° Au milieu des renseignements precis et des opinions tres-sensees de MM. Benoiston de Ch6,teauneuf, Galton, et autres statisticiens, je n'ai pas rencontr6 la reflesion bien importante qu'ils auraient dit faire de l'extinction inevitable des noms defamine. Evidemment tons les noms doivent s'eteindre Un mathematicien pourrait calculer comment la reduction des noms ou titres aurait lieu, d'apres la probabilite des naissances toutes feminines ou toutes masculines ou melangees et la probabilite d'absence de naissances dans un couple quelconque," etc.-Alphonse de Candolle, " Histoire des Sciences et des Savants," 1873.