Sex-reversal following ovariotomy in the fowl.

Abstract

It has been known for a considerable period of time that the female in many breeds of birds takes on certain male characters following the removal of the ovary, either by ovariotomy or pathological absorption. In the latter case the reduction of the ovarian mass may be only partial or for a short period of time, followed by recovery and regeneration of the ovary; or the ovary may be permanently reduced and destroyed. In all such cases the female assumes certain male characters, and the extent to which such male characters are developed and their permanency, apparently depends upon the degree of removal or reduction of the ovary.

It is the purpose of this paper to call attention to experiments being carried on in this laboratory which have a very special bearing on some of the work recently reported by Crew 1 in the fowl, and by Riddle 2 in the pigeon. Investigations along this line were suggested by Professor F. R. Lillie, early in the fall of 1922, and have been carried on under his direction. 3

My work thus far has been confined exclusively to the Light Brown Leghorn race. Sexual dimorphism is this breed is very pronounced, and the birds are more active and perhaps somewhat more hardy than are the birds of some of the heavier breeds. Most of the birds were obtained from a reliable breeder immediately after hatching and reared in the laboratory, where operations could be made at various ages and results observed.

The operation in the female is relatively difficult, owing to the proximity of the great blood vessels. In the young female, prior to the age of laying, the ovary is a flat sheet of tissue attached intimately by one surface to the ventral surface of the left iliac and vena cava. It was found that the ovary is most readily and most satisfactorily removed during this stage of its development. If the operation is delayed until the changes preceding the laying season have set in, the ovary has enlarged and has become more extensively vascularized, and its removal is more difficult.