GENERATION. 



when feen at a little diftance. Wlien there is only one 

 child, there is only cni corpus luteum ; and two in cafe of 

 twins. There may be, in the latter cafe, two diftinft ones in 

 one ovarium, or one in each ovarium. The fex of the foetus 

 has no relation to the corpus luteum being formed in the 

 right or left ovary. 



Th'icknefs of the Uterus. — Thofe who fay that the uterus 

 grows thicker in proportion as its bulk i.-; increafed.have pro- 

 bably been deceived by examining the uterus of a woman 

 who died fome hours or days after delivery. In that con- 

 trafted ftate the uterus is often found even two inches thick : 

 but in the natural diftended ftate, though there may be fome 

 difference, the thicknefs, in general, is but little more con- 

 fiderable than before impregnation. When not injefted, its 

 ordinary thicknefs is from one to two-thirds of an inch ; 

 when its velTels, and particularly the veins, are pretty well 

 filled with wax, its thicknefs is tk.neby coniiderably increaf- 

 ed, more efpecially where the placenta is fixed, on account 

 of the number and fize of the veflels at that part. For this 

 reafon only, perhaps, the uterus is thickeft at that part, and 

 for the fame reafon it is thicker towards the fundus than near 

 the cervix. Much variety may be obferved with refpeit to 

 thicknefs : and fuch inequalities in the fame individual, tliat 

 even where the placenta did not adhere, the uterus may be 

 almofl: twice as thick at one part as at another. On open- 

 ing the organ, its thicknefs is generally found more confi- 

 derable than external exainination would have led us to ex- 

 peft. For its fubftance is foft, and a fludluation, like that 

 of water in a thin bladder, may be felt. 



Blood-veJJlh. — There is no circumftance, in which the 

 gravid uterus differs more from the unimpregnated, than in 

 the fize and termination of its vefTels. The arteries, both 

 fpermatic and hypogaitric, are very much enlarged. There 

 are infinite numbers of anaftomofing arteries through the 

 whole fubftance of the part, fo that the wliole fyftem 

 makes a general net-work, and the branches are convoluted 

 or ferpentine in their courfe. None of the larger ramifi- 

 cations are fccn for any length of way upon the outlide of 

 the uterus. As they branch from the fides, they difappear 

 by plunging deeper and deeper into the fubft:ance. The 

 arterial branches, which are much enlarged, are thofe which 

 run towards the placenta ; fo that, v.-herever it adheres, that 

 part appears evidently to receive by far the greateft quantity 

 of blood ; and the greateft number, both of the large and 

 fmal! arteries at that part, pafs through to the placenta, and 

 are necetTarily torn through upon its feparation. The veins 

 of the uterus appear to be ftill more enlarged, in propor- 

 tion, than the arteries. From the fides of the uterus they 

 ramify through its fubftance, running deeper and deeper as 

 they go on, and without following precifely the courfe of 

 the arterial branches. They form a plexus of the largeft 

 and moft frequent communications which we know of 

 among the vefTels of the human body. And this they 

 have in common with the arteries, that their larger branches 

 go to, or rather come from that part of the uterus to 

 which the placenta adheres ; fo that, when the venous fyftem 

 of the uterus is well injetted, that part is evidently the 

 chief tource of the returning blood. Here, too, both the 

 large and fmall veins are continued from the placenta to 

 the uterus, and arc alvvays neceffarily broken upon the 

 feparation of thefe two parts. The veins are without valves, 

 and are therefore eafdy injefted. In injecling them, 

 we obferve that at firft they become turgid, and projeiit on 

 the outer furface of the uterus ; but in proportion as we 

 throw a greater quantity of wax into thefe vefTels, they 

 grow more flat and obfcure ; becaufe the uterus itfelf be- 

 «omes more filled and tcnfe, which has the effed of coni- 



prefTing the veins that run in its fubftance. On account of 

 the large fize of thefe vefFels, and the appearance of cavities, 

 which they exhibit on a feftion, the name of finufes has 

 fonietimes been given to them. 



The lymphat'ics are m.ore numerous, and many of them 

 larger than could have been imagjined. They pervade the 

 fubftance of the organ univerfally. Its peritoneal coat ap- 

 pears, like that of a calf's fpleen, to be interwoven with a 

 crowded plexus of thefe vefTels ; and where they get to the 

 fides of the uterus, when filled with mercury, fome of them 

 are even larger than a goofe's quill. Some are remarkably 

 varicous, or enlarged at particular places. 



We do net know that any change takes place in the 

 nerves of the uterus during pregnancy. 



Mufcular Fibres of th: Uterus The fubftance of the or- 

 gan is rendered remarkably fofi and loofe in its texture by 

 pregnancy ; fo that, when an incifion is made into it, the 

 wound can be eafily made to open wiJe ; or if a narrow Urip 

 be cut out, it can readily be extended to at leaft twice its 

 original breadth. This laxity appears to depend on two 

 caufes ; -ulz. the great quantity of large vefTels in its com- 

 pofition ; and the loofe connexion between the fafcicuh of 

 its fibres. When we fpeak of the mufcidar fibres, it is dif- 

 ficult to treat the fubjcct wnth precifion. We neither kn w 

 theirexternal appearance, nor their internalcompofition. 1 hey 

 only manifefl themfclves to our fenfes, where numbers of them 

 are coUefted into bundles, and make what we commonly call 

 mufcular fafciculi. In the quadruped, as, for inftanc-, the cat 

 or rabbit, the mufcular adlion of the uterus is feen as evidently 

 as that of the inteftines, when the animal is opened immedi- 

 ately after death. In many parts, particularly cf the internal 

 furfaceof the uterus, thefe fibres have the fame ftriking fafcicu- 

 lated appearances as we obferve in common mufcles ; yet they 

 are of a paler coloiir and harder texture. Dr. Hunter exa- 

 mined the fibres very can-fully in a woman who diedfeven da)-^ 

 after dehvery. He ftretched it gradually in warm water, and 

 then inverted it, to have a full view of the inner furfr.ce. 

 The remains of the decidua had pafTed off with the lochia, 

 fo that the fafciculated flratum of mufcvJar fibres appearea 

 to be bare, and to make the internal furface of the uterus. 

 In many places, but particularly where the placenta had beesi 

 fixed, the fafciculi left oval fpaces between them, for the 

 pafTage of arteries and veins, fomev.hat like thofe fepara- 

 tions in the tendinous fibres of the abdomen and loins, where 

 vefTels pals out to the cellular membrane and integuments. 

 The cervix uteri, where the rugoe are fituated, had not fuch 

 regular nor fo large fafciculi as the reft of the ttterus. In 

 the body of the organ the fibres were very regularly circular. 

 The fundus was made up of two planes of concentric fibres, 

 at tlie very centre of which was the orifice of the Fallopian 

 tube. When this internal ftratum was removed, the fafci- 

 culated appearance and regular direction of the fibres was 

 lefs and lefs apparent, in proportion as the diffection was 

 continued outwards; which feemed to be o-.nng in great 

 meafure to the infinite number of branches and comm.unica- 

 tions of the large veins. Afterwards, fays the doctor, I 

 had tlie moft favourable occalion that could be defired, for 

 examining the fibres on the infido-of the uterus. It was in 

 a woman wh.o died at the end of the ninth month, without 

 being in labour, and v.ithout having any flooding or dif- 

 charge of waters. When I had examined, and taken 

 out all the contents, I attended particiilaily to the internal 

 furface of the uterus. I found it every w'u-re covered witli 

 a thin ftratum of the d'cidua, tlirough which the mufcular 

 fibres appeared, but with fume degree of obfcurity. Upon 

 rubbing off this tender niembrane with a cloth, it gave me 

 H 2 pleafure 



