to elucidate the phenomena, so that this particular explanation cannot be overlooked.
4. There remains, however, the question which many people have rushed in to discuss—viz., whether the reproductive power of the populations in question is quite as great as it was fifty or sixty years ago. We have already heard in some quarters, not merely that the reproductive energy has diminished, but suggestions that the populations in question are following the example of the French, where the rate of increase of the population has almost come to an end. Apart, however, from the suggestions above made as to the abnormality of the increase fifty or sixty years ago, so that some decline now is rather to be expected than not, I would point out that the subject is about as full of pitfalls as any statistical problem can be, for the simple reason that it can only be approached indirectly, as there have been no statistical records over a long series of years showing the proportion of births to married women at the child-producing ages, distinguishing the ages, and showing at the same time the proportion of the married women to the total at those ages. Unless there are some such statistics, direct comparisons are impossible, and a good many of the indirect methods of approaching the subject which I have studied a little appear, to say the least, to leave much to be desired. We find, for instance, that a comparison has been made in Australasia between the number of marriages in a given year or years and the number of births in the five or six years following, which show, it is said, a remarkable decline in the proportion of births to marriages in recent years as compared with twenty or thirty years ago. It is forgotten, however, that at the earlier dates in Australasia, when a large immigration was taking place, a good many of the children born were the children of parents who had been married before they entered the country, while there are hardly any children of such parents at a time when immigration has almost ceased. The answer to such questions is in truth not to be rushed, and the question with statisticians should rather be how the statistics are to be improved in future, so that, although the past cannot be fully explained, the regular statistics themselves will in future give a ready answer.
5. One more remark may, perhaps, be allowed to me on account of the delicacy and interest of the subject. To a certain extent the causes of a decline in reproductive energy may be part and parcel of the improved condition of the population, which leads in turn to an increase of the age at marriage, and an increase of celibacy generally through the indisposition of individual members of the community to run any risk of sinking in the scale of living which they may run by premature marriage. These causes, however, may operate to a great extent upon the birth-rate itself without diminishing the growth of