652 



UTERUS AND ITS APPENDAGES. 



or conductor of nerve force, the former pro- 

 perty belonging exclusively to the nerve 

 centres, and the latter to the nerve tubes or 

 nerve fibres. It is therefore necessary to as- 

 certain if either nerve centres or nerve fibres 

 become in any way multiplied or enlarged 

 during the process of utero-gestation. 



Regarding a new formation of nerve centres, 

 there is at present no anatomical proof that 

 any fresh ganglionic corpuscles are formed 

 during pregnancy within the ganglia or 

 plexuses from which nerves proceed to the 

 uterine tissues. 



Regarding the changes which take place in 

 the nerve tubes or fibres during gestation, 

 much interesting information is obtained from 

 the researches of the late Dr. Franz M. Kilian, 

 who devoted a considerable time to the in- 

 vestigation of this point. Dr. Kilian dis- 

 covered, that in the unimpregnated uterus a 

 successive diminution of the nerve fibre, 

 whether in bundles or isolated, takes place as 

 it approaches the point of distribution. If 

 broad, the fibre, after a certain portion of its 

 course, begins to lose its greater breadth, dis- 

 tinct double contour, and strongly marked 

 granular contents, and then continuing as a 

 pale fibre of intermediate size until it ap- 

 proaches nearer to the uterus, it ultimately 

 assumes an embryonic character ; that is, 

 the extremely attenuated pale-margined fibre 

 which traverses the tissues as a slender trans- 

 parent band, has ceased to form a cylinder 

 filled with nerve granules, and constitutes 

 now only a pale slender stripe, or empty non- 

 medullated sheath. Within this empty sheath 

 there still occur, at distant intervals, little 

 collections of granular fatty contents. 



Now, in the early periods of pregnancy 

 these embryonal forms are observed to be- 

 come gradually more distinct between the 

 muscular fibres, and at a later period many 

 of the fine tubes become filled with medulla, 

 which was wanting in the unimpregnated con- 

 dition ; the little collections of granular fatty 

 contents just mentioned constituting the 

 commencement of the nerve cylinders. For 

 it is by the confluence of these isolated drops 

 within the sheath that the medullated cylinder 

 is formed, so that mednllated fibres not only 

 proceed as far as the uterus, but also become 

 developed with continually increasing dis- 

 tinctness during pregnancy between the mus- 

 cular fibres. 



These observations correspond exactly with 

 changes which Kilian observed to take place 

 also in j'oung animals, when the nerve fibres 

 in the neighbourhood of the uterus are all in 

 the embryonic condition, but become gradually 

 medullated up to a certain point, in propor- 

 tion as the development of the animal pro- 

 ceeds, so that the nerves may be said to grow 

 forward in the direction of the uterus. 



It should be understood, however, that in 

 all these cases, the dimension of the nerve 

 fibre never exceeds that of the branch whence 

 it is derived, but that, on the contrary, a law 

 of gradual diminution of the nerve is found 

 to obtain in all cases, although the changes 



now described cause the rate of this to be 

 different in the unimpregnated and gravid 

 uterus respectively. 



Kilian had no opportunity of examining the 

 condition of the nerves in the human uterus 

 at different periods of pregnancy, but he doubts 

 not that the alterations are analogous to those 

 which he found in animals. 



The lining membrane of the uterus. Develop- 

 ment of the decidua. The last, and at the 

 same time the most interesting, transforma- 

 tion of the uterine tissues remains to be de- 

 scribed. It is that which takes place in the 

 lining membrane, and which has for its object 

 the formation of an immediate covering and 

 protection to the ovum. By the aid of this 

 membrane, the fertilised ovum, on arriving 

 loose in the uterine cavity, is re-attached to 

 the parent body, and is enabled to receive 

 from it the supplies necessary for nutrition 

 and growth. 



But before the ovum enters the cavity of 

 the uterus, the lining membrane of the latter 

 swells and becomes softer and at the same 

 time more vascular.* This augmentation in 

 bulk of the uterine inner coat takes place in 

 almost all cases when an ovum has been fer- 

 tilised. That it does not depend upon the 

 presence of the ovum in the uterus, is proved 

 by the fact, that in cases of extra-uterine ges- 

 tation, with rare exceptions, a development of 

 decidua occurs within the uterus, forming 

 there, in some cases, a more profuse growth 

 even, relatively to the size of the uterus, than 

 takes place in ordinary gestation. 



The phenomena which ensue immediately 



* In a paper on the Structure of the Placenta, 

 by John Hunter, published in 1786 (Animal Eco- 

 nomy), the decidua is described as composed of 

 coagulable lymph. In another paper, 1794, on " the 

 case of a young woman who poisoned herself in the 

 first month of pregnancy," the pulpy substance 

 lining the uterus, into which the blood-vessels of 

 the uterus passed, and upon which they ramified, 

 is stated to have consisted evidently of blood coagu- 

 lated. The statements and descriptions in these two 

 papers constitute the basis of the Hunterian hypo- 

 thesis regarding the source of the decidua. But 

 Dr. William Hunter had, even at that early period, 

 a clearer perception of what the decidua really was, 

 for in his posthumous work entitled "An Anato- 

 mical Description of the Human Gravid Uterus," 

 edited by Dr. M. Baillie in 1794, the decidua is de- 

 scribed in the following phrases: "This mem- 

 brane is an efflorescence of the internal coat of the 

 uterus itself." ..." It may be said to be the internal 

 membrane of the uterus." ..." It is really the inter- 

 nal lamella of the uterus." That the decidua con- 

 stitutes simply a higher stage of development of 

 the lining membrane of the unimpregnated uterus, 

 in the same way that the muscular coat of the gra- 

 vid organ is only a more advanced condition of the 

 same coat before impregnation, is now proved be- 

 yond question. Upon this subject consult, in addi- 

 tion to the works quoted at p. C3t>., Sharpey, in 

 " Miiller's Physiology, by Baly," 1837, p. 1574. ; 

 Eschricht, " De Organis qua? Respirationi et Nutri- 

 tion! Foetus Mammalium inserviunt," 1837 ; F. M. 

 Kilian, " Die Structur des Uterus bei Thieren," in 

 Henle and Pfeufer's Zeitschrift, bd. ix. ; Schroeder 

 van der Kolk, " Waarnemingen over Het Maaksel 

 van de Menschelijke Placenta;" and Coste, " His- 

 toire Ge'ne'rale et Particuliere du De'veloppement 

 des Corps Organises." 



