Talk:Paper - The lower ends of the wolffian ducts in a female pig embryo (1914)

From Embryology

THE LOWER ENDS OF THE WOLFFIAN DUCTS IN A FEMALE PIG EMBRYO. By FrRepeEric Woop Jonss, D.Sc., The London School of Medicine for Women.

THE present communication is intended to deal-with a mere presentation of the conditions that are actually illustrated; and, like a previous communication on the External Genitalia of the Human Female (Jowr., xlviii. p. 73), is to be regarded only as an isolated study carried out as part of a wider survey of the mammalian genitalia. The sections which are illustrated were cut some ten years ago. The facts which they illustrate are by no means new, but I think it is advisable to record them as showing a definite phase in the evolution of the genital ducts in the pig. The stage recorded and illustrated is that found in foetuses of 12 centimetres rump-vertex length. The series of sections is shown in order from head to tail, and the photographs represent on the average every fifth section of the series.

In the most cephalad sections (see figs. 1 and 2) the fused Mullerian ducts have constituted a wide and patent canal (vagina, fig. 1), seen upon the dorsal side of the section, and towards the ventral side of the section is the cavity of the urethra, both chambers being surrounded by a well-defined common musculature.

Upon the ventral aspect of the fused Mullerian ducts, and embedded in their mesenchyme stroma, are the minute Wolffian ducts (W.D.).

As the sections are traced towards the caudal end, the lumen of the Mullerian ducts diminishes and becomes again bilateral by the closure of the central part of the canal (see fig. 3). After a short distance traversed in this fashion, even the bilateral Mullerian elements become reduced to solid columns of cells (see fig. 4).

Meanwhile the lumen of the Wolffian ducts is becoming increasingly large.

Still further towards the hind end the solid Miillerian columns become difficult to trace, and are closely applied to the dorsal aspects of the everenlarging Wolffian ducts (see figs. 5 and 6).

In the section represented in fig. 7, the two enlarged Wolffian ducts have met and fused in the middle line, forming a single median Wolffian chamber ; and the Miillerian elements have become still further reduced. The Lower Ends of the Wolffian Ducts in a Female Pig Embryo 269

Finally, in the section shown in fig. 8, the Wolffian chamber has opened into the urinary canal, forming a uro-genital sinus.

I think it is not unreasonable to interpret the condition shown as being a definite phase in the development of the female pig embryo, in which the Wolffian ducts are the only genital channels opening into the uro-genital sinus. In this phase the Miillerian ducts are reduced to solid epithelial cords, and the uterine cavity has no outlet into the uro-genital sinus. The single median genital opening is a Wolffian chamber into which apparently the Miillerian ducts will open when they become patent later on in foetal life. .

For the production of the microphotographs which illustrate this paper

(pp. 270-273) I am indebted to the kind help and skilled assistance of the Anatomical Department of King’s College.

[Fies. 1-8. 270 Mr Frederic Wood Jones

Fic. 1. The Lower Ends of the Wolffian Ducts in a Female Pig Embryo 271

~~ solid epithelial vagina.

Fig, 4. 272 , Mr Frederic Wood Jones

Fia, 5.

Fie. 6. The Lower Ends of the Wolffian Ducts in a Female Pig Embryo 273

— W.D. fused.

Fia. 7.

Fic. 8.