654 



UTERUS AND ITS APPENDAGES. 



vations, and between these much smaller cup- 

 like or conical depressions, which are seen by 

 transmitted light to lead, where the membrane 

 is thinnest, directly into the apertures ob- 

 servable on the inner surface. At the thin- 

 nest points of all, these apertures are so wide, 

 and the cup-like depressions so shallow, that 

 the part has the appearance of a net, the 

 meshes of which still consist of the enlarged 

 orifices of the utricular glands. Hence the 

 epithet " lace-like," often applied to the de- 

 cidua in this condition. 



The roughness of the dorsal surface of this, 

 the parietal decidua, is occasioned by the 

 membrane having been torn away from its 

 connexion with the muscular coat of the 

 uterus, in the act of abortion. The club-like 

 projections are apparently the bases or blind 

 ends of the hypertrophied utricular glands 

 torn out entire from the substance in which 

 they were previously embedded. When laid 

 open, they are found to contain a small cavity. 

 The cup-like depressions are the halves, or 

 portions of similar, perhaps smaller glands, 

 torn across, so as to leave other portions still 

 attached to the uterus. The meshes are 

 simply the orifices of such glands and of the 

 channels leading to them. 



At this and subsequent stages thene may 

 be often seen lying within and among these 

 orifices, fine, thread-like ramified filaments, 

 which some physiologists suppose to be utri- 

 cular glands, or their epithelial lining, now 

 becoming loosened out and falling away, a 

 view in which my own observations do not 

 enable me to coincide. Seej%. 451. 



Fig. 451. 



seen, more or less distinctly, in the decidua 

 throughout pregnancy, but are most conspi- 

 cuous near the margins of the placenta. 



Fig. 452. 



External surface of the decidua vera, from an ovum 

 of about two months ; showing the oblique channels 

 in its substance. (After Schrceder van der Kolk.) 

 a a a, filaments supposed to be the loosened utricu- 

 lar glands (?) 



As pregnancy advances to the third and 

 fourth months, the uterine chamber expands, 

 the decidua which lines it increases in thick- 

 ness in parts to 3 4'", and becomes at the 

 same time more spongy, so that upon section 

 it appears to be composed of flattened spaces 

 or cells, communicating together by wide 

 valvular orifices. These are best seen by 

 examining under water the rough surface 

 of an aborted ovum at that period, or the 

 corresponding portion of the uterus from 

 which it had been torn off. (Fig. 452.) 

 These cells, or areolar spaces, continue to be 



Surface of the decidua vera more advanced. (After 

 Schrceder van der A'oZ/i.) 



It is here represented as still attached to the walls 

 of the uterus after the chorion, together with a layer 

 of the decidua, have been peeled off from it. From 

 a uterus at the sixth month of pregnancy, just 

 beyond the margin of the placenta. The orifices 

 and canals are much wider than in the first figure. 



They are still divisions of the same ramified 

 canals, or uterine glands, which have been 

 described as found everywhere in the lining 

 membrane of the uterus before impregnation, 

 fig. 438., but now become so dilated and tor- 

 tuous as scarcely to be recognisable as the 

 same structures.* 



In the latter months of pregnancy, the 

 parietal decidua becomes thinner, and loses 

 much of its spongy character, except imme- 

 diately around the placenta, where this is 

 still most distinct. It ultimately becomes 

 blended with the outer surface of the foetal 

 membranes, and is partly thrown off with them 

 in the act of birth, while a part remains, form- 

 ing a honeycomb layer, attached to the uterine 

 muscular coat. 



If next the growth of the decidua reflexa, 

 or decidua ovuli, be traced, this will be found 

 to undergo a development corresponding with 

 that of the ovum, which it encloses and pro- 

 tects. The little chamber containing the 

 ovum, which, as already stated, usually occu- 

 pies a situation near one of the upper uterine 

 angles (^g.450.), although it may also be found 

 near the lower orifice ( Hunter, " Gravid 

 Uterus," pi. 34., Jig. 4.), or elsewhere, appears 

 at first like a small superadded cavity upon the 

 outside of the larger one, or that formed by the 

 parietal decidua. But as the development pro- 

 ceeds, the foetal protrudes gradually into the 

 uterine chamber, in the form of an incomplete 

 sphere, whose upper pole rises free into the 



* The four figures 450, 451, 452, and 453., show- 

 ing the decidua or lining membrane of the uterus in 

 different stages of development during pregnancy, 

 should be compared with figs. 438, 439. and 443., 

 which exhibit the same structure in different con- 

 ditions of the unimpregnated state. These struc- 

 tures form a developmental series, the individual 

 stages of which are often dislocated from their true 

 and natural sequence by the employment of terms 

 calculated to give an impression 'that the parts 

 spoken of are different in structure and composition. 

 " Mucous or lining membrane of the uterus," 

 " L3'mph," and " Decidua," when so employed, 

 should be read as convertible terms representing' the 

 same part in different stages of development. 



