THE SEXUAL ORGANS. 263 



nerve-fibres in the trunks, and regards such an occurrence as 

 improbable ; for otherwise a new formation of ganglionic sub- 

 stance must also be assumed, which is unlikely. Something 

 of the kind appears to me by no means impossible, because the 

 multiplication of the ganglion-cells and of the fibres would only 

 take place once — in the first pregnancy; it is also conceivable 

 that newly formed nerve-fibres are added to the others simply 

 as branches, and consequently it will be more prudent to wait 

 and see upon which side Remakes statements, with respect to 

 the human subject, incline. Upon this, however, I would also 

 remark, that a thickening of the nerves may undoubtedly be 

 produced by an increased size of the already existing fibres and 

 an augmentation of the neurilemma, and that the nerves, by a 

 multiplication of their ultimate divisions, are fully enabled to 

 ramify over larger spaces than at other times. 



The increased size of the vessels, both of the arteries, and, 

 above all, of the veins, at the time of pregnancy, is very con- 

 siderable ; owing to which, at this period, the middle layer of 

 the muscular substance, containing the larger vessels, is much 

 more distinct from the other two. The alteration which takes 

 place in the vessels of the mucous membrane, at the point 

 where the placenta is formed, cannot here be entered upon ; 

 and I will only remark that I agree with those who believe 

 that large vascular trunks exist in the human uterine placenta, 

 at the border and on the convex surface, whilst in the interior 

 there are only lacuna without walls, between the villi of the 

 chorion (vide Kiwisch, f Geburtskunde/ I, p. 151, et seq.; C. 

 Wild, ' Zur Physiologie d. Placenta/ Wurzb., 1849; Virchow, 

 < Archiv/ III, p. 449 ; Schroder v. d. Kolk, in the ' Verh. d. 

 Nied. Instituts/ 1851). In the rest of the decidua, the capil- 

 laries are frequently excessively enlarged ; according to Virchow 

 (' Archiv. f. path. Anat./ Ill, p. 436), its superficial capillaries, 

 in the sixth week of pregnancy, reach the size of 0027 — 

 , 045 /// , and become extremely thin-walled, as are, probably, 

 also those in the part where the placenta is situated, before 

 their walls disappear and their cavity is thrown into that of the 

 lacunae. In the venous trunks of the gravid uterus, besides the 

 circular muscular layer, with much enlarged fibre-cells, which 

 exists also in other situations, I have found an external and in- 

 ternal longitudinal muscular layer with similar colossal elements ; 



