ORGANS OF THE BODY. 547 



place, the process is carried on with greater tardiness : the yellow body 

 increases in magnitude, remains for some months at a high degree of 

 development, and only recedes after /our or five months. At the end 

 ' of pregnancy it has not yet disappeared. These differences appear to be 

 occasioned by the continuous increase of vascularity in the organs of 

 generation in the latter case, compared with the more transitory excite- 

 ment in the first instance. The corpora lutea have been classified, owing 

 to this, into true and false. 



279. 



We now turn to the consideration of the Fallopian tubes and 

 uterus. 



The first of these may be divided into two portions, namely, an upper 

 and more or less tortuous half of greater diameter, known as the am/pulla, 

 of Henle; and an inferior and much narrower half, which leads into the 

 uterus, the isthmus of Barkow. They present an external layer of con- 

 nective-tissue belonging to the peritoneum, and beneath this a muscular 

 tunic, consisting of longitudinal involuntary fibres, on the outside, and 

 transverse fibres within. The cells of this coat, largely intermixed with con- 

 nective-tissue, are extremely difficult to isolate. During pregnancy this is 

 somewhat easier. The mucous membrane of the tubes is entirely destitute 

 of glands. In the isthmus it is covered with small longitudinal folds ; 

 in the ampulla with a series of very considerable ones, which are supplied, 

 as I find in the pig, with a very complex network of looped vessels, and 

 almost close the lumen completely. Its ciliated epithelium (p. 150), 

 which extends as far as the external surface of the firnbrise, moves in a 

 ciliary wave directed towards the uterus. As in the mucous membrane 

 of the uterus, so also here do we miss those goblet cells described by 

 Scliulze. 



The uterus or womb, although it undergoes numerous changes during 

 the earlier periods of existence, owing to the processes of menstruation 

 and pregnancy, is nevertheless in many points similar in structure to the 

 tubce Fallopii. Its muscular tissue is, however, of greater strength, and 

 its mucous membrane contains glands. 



The fleshy mass of the uterus consists of transverse, oblique, and longi- 

 tudinal bundles of smooth muscular fibres, interlacing in every conceiv- 

 able direction (p. 283). To a certain extent we may distinguish three 

 layers, of which the middle is the thickest. Around the neck of the 

 womb the fibres are arranged in transverse bundles, so as to form a regu- 

 lar sphincter uteri. In this neighbourhood the contractile fibre-cells 

 are particularly difficult to isolate if the organ is not in the gravid con- 

 dition. 



In the mucous membrane of the uterus (which is closely adherent to the 

 muscular tissue, and exchanges with it many of its elements of form), we 

 find both in the body and cervix a network of stellate and fusiform 

 cells similar to those of the framework of lymphoid organs (Henle, Lind- 

 gren). 



Those bands of smooth muscular fibres which extend into it appear to 

 terminate in its deeper strata. The mucous tissue of the vaginal portion 

 was found by Lindgren to be traversed by vertical bands of elastic fibres, 

 connected with one another in arches near the surface. The body and 

 parts of the neck also of the uterus present ciliated epithelial elements, 

 described at a very early period as simple columnar cells without cilia. 



