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PROPORTION OF THE SEXES IN HORSES AND OTHER DOMESTICATED ANIMALS.

Sir,— Mr Chas. Darwin has recently written to me, stating that he is anxious to ascertain the relative proportion of births of males and females in as many domestic animals as possible, such as poultry, ducks, pigeons, canaries, horses, dogs, sheep, cattle, asses, rabbits, &c.

By referring to the Racing Calendar for the last two-and-twenty years (since 1846 inclusive), I have ascertained the proportion of thoroughbred colts and fillies foaled during that period; they amount to 12,763 colts, and 12,797 fillies, showing a difference of thirty-four in favour of the fillies, or one in every 751. I believe the general impression abroad is that the fillies are considerably in excess of colts. They have been so during the past four years, which show 3241 fillies against 3102 colts; but the average drawn from more extended experience afforded by twenty-two years corrects the error, and shows how very slight the preponderance of one sex is over the other.

May I ask those persons who can assist in this inquiry to forward any facie bearing on the matter? I ask this not as personal favour, but in the interests of scientific research.

W. B. Tegetmeier.