paired by the furious rate of our business and social life. According to this view, the diminishing birth rate is not due to the under-nutrition of the reproductive organs, but rather to a breakdown in the machinery which normally controls their functioning.
In further support of his position, the biologist rests his case upon an inference. Observing that the higher animals are less prolific than the lower, he concludes that fecundity among the more advanced types of the human race is necessarily smaller than among the less advanced. Or taking his clue from the fact that wild animals when made captive become less fertile, he asserts that the industrial and social changes of the last fifty years have had a similar effect upon the human race.
Finally, the explanation of the biologist is occasionally supplemented by that of the medical expert who emphasizes the amount of involuntary sterility induced by sexual diseases. Modern transportation and the growing density of population, together with the increase of wealth and leisure, are said to spread the taint of sexual disorders by making possible more promiscuous relations between the sexes. The immoral relations which wages insufficient for self-support or for an attractive manner of dress tempt some young women to sustain are now and then mentioned as a contributory factor.
While conceding a certain force to the position of the biologist and the medical expert, the economist insists that it offers a far from satisfactory explanation of the phenomenon in question. Doubtless sexual diseases account for a good deal of involuntary sterility. Some authorities hold venereal diseases responsible for fully twenty-five per cent. "of the inability to procreate in man," and for more than fifty per cent, "of enforced sterility in woman, to say nothing of the one-child sterility where the conceptional capacity is absolutely extinguished with the birth of the first child." This leaves us quite in the dark, however, concerning the proportion which sterility that is involuntary is of the sum total of all kinds. More important still, there is little evidence that incapacity due to sexual diseases has become more common. The fact that existing conditions afford greater opportunity for the spread of such diseases no more proves that this has actually occurred than the increase of positions of trust proves the increase of theft. For the achievements of modern civilization are scarcely reconcilable with either the increase of dishonesty or with growing laxity in the sexual relations. Nor do the temptations incident to low wages prove that an increasing proportion of women lead lives that are impure. Certain it is that economic independence was never so consistent with chastity among women as to-day. Moreover, it is not clear that venereal diseases are most common in that portion of the popu-