THE UTEKUS. 281 



that time, ten or fifteen times as long and five or six times 

 as broad as they are in the unimpregnated state. They are 

 united into bundles, or fasciculi, which, in certain of the lay- 

 ers, interlace with each other in every direction. 



It is quite difficult to follow out the course of the f asc> 

 culi of the uterus, and the layers are described somewhat 

 differently by different writers. All agree, however, that 

 there is a superficial layer, tolerably distinct, very thin, re- 

 sembling the platysma myoides, which is sometimes called 

 the platysma of the uterus. In addition to this layer, we 

 shall describe two ; making, in all, three layers, an external, 

 middle, and internal, though this division is . somewhat arbi- 

 trary. 



The external layer, very thin but distinct, is closely at- 

 tached to the peritoneum. When the uterus is somewhat en- 

 larged after impregnation, we observe oblique and transverse 

 superficial fibres passing over the f undus and the anterior and 

 posterior surfaces to the sides. Here they are prolonged into 

 the Fallopian tubes, the round ligament, and the ligament of 

 the ovary, and also extend between the layers of ihe broad 

 ligament. This external layer is so thin that it cannot be very 

 efficient in the expulsive contractions of the uterus ; but, from 

 its connections with the Fallopian tubes and the ligaments, it 

 is useful in holding the uterus in place. It does not extend 

 entirely over the sides of the uterus. Rouget, who has given a 

 very elaborate description of the external layer in the human 

 subject and in various classes of animals, has found it pro- 

 longed into the ligaments and extending to the ovaries and 

 Fallopian tubes. He regards the uterus and its so-called ap- 

 pendages as lying between two thin, muscular sheets, and 

 considers the action of the muscular fibres as very efficient in 

 producing an engorgement of the erectile tissue of the inter- 

 nal organs, by constriction of the veins. Erection, according 

 to this observer, occurs at the period of menstruation, deter- 

 mines the application of the fimbriated extremity of the Fal- 

 lopian tubes to the surface of the ovary, and assists in the 



