by nearly all calm and sagacious inquirers.41 The wild outcry of many unbalanced persons to-day, that a falling birth-rate means degeneration and disaster, is so altogether removed from the sphere of reason that we ought perhaps to regard it as comparable to those manias which, in former centuries, have assumed other forms more attractive to the neurotic temperament of those days; fortunately, it is a mania which, in the nature of things, is powerless to realize itself, and we need not anticipate that the outcry against small families will have the same results as the ancient outcry against witches.42
It may be proper at this stage to point out that while, in the foregoing statement, a high birth-rate and a high marriage-rate have been regarded as practically the same thing, we need to make a distinction. The true relation of the two rates may be realized when it is stated that, the more primitive a community is, the more closely the two rates vary together. As a community becomes more civilized and more complex, the two rates tend to diverge; the restraints on child-production are deeper and more complex than those on marriage, so that the removal of the restraint on marriage by no means removes the restraint on fertility. They tend to diverge in opposite directions. Farr considered the marriage-rate among civilized peoples as a barometer of national prosperity. In former years, when corn was a great national product, the marriage-rate in England rose regularly as the price of wheat fell. Of recent years it has become very difficult to estimate exactly what economic factors affect the marriage-rate. It is believed by some that the marriage-rate rises or falls with the value of exports.43 Udny Yule, however, in an expertly statistical study of the matter,44 finds (in agreement with Hooker) that neither exports nor imports tally with the marriage-rate. He concludes that the movement of prices is a predominant—though by no means the sole—factor in the change of marriage-rates, a fall in prices producing a fall in the marriage-rates and also in the birth-rates, though