It has been facetiously said that facts alone are more unreliable than statistics. However that may be, according to the late Dr. Matthews Duncan, the comparative fertility of the human female "increases gradually from the commencement of the child-bearing period of life until about the age of thirty years is reached, and that then it still more gradually declines," and "that it is greater in the decade of years following the climax of about thirty years than in the decade of years preceding the climax." The same author states that 15 per cent, of married women, between the ages of 15 and 45 years, are found to be sterile; others claim the proportion to be one in 8.5, one in 10, etc.
Sterility chargeable upon the female alone during the period of reproduction is rare in the domestic animals, and when existant is usually caused by some obstruction, congenital or