barrenness, in opposition to fertility. It has been affected by many authors, that all monsters produced by a mixture of different species of animals, such as mules, are barren; but this does not hold universally, even with the mule, which is the instance most generally adduced.

Sterility in women sometimes happens from a miscarriage, or violent labour injuring some of the genital parts; but one of the most frequent causes is the suppression of the menstrual flux.—There are other causes arising from various diseases incident to those parts, by which the uterus may be unfit to receive or retain the male seed;—from the tubes fallopianae being too short, or having lost their erectile power; in either of which cases no conception can take place;—from universal debility and relaxation; or a local debility of the genital system; by which means, the parts having lost their tone or contraftile power, the semen is thrown off immediately post coition;—from imperforation of the vagina, the uterus, or the tubes, or from discoloured ova, &c. Hence medical treatment can only avail in cases arising from topical or universal debility; in correcting irregularities of the menstrual flux, or in removing tumors, cicatrices, or constrictions of the passage, by the art of surgery.