RobertC. Croft
1856 The Lancet  
205 After examining the parts in their natural position, I removed them, and hastened home to place the whole in warm water. Then, having cleared the placenta of as much blood as possible, taking care that the water in the basin remained warm and clean, I injected into the umbilical vein a large quantity of warm water coloured. This was done with the intention of learning whether any of it would pass into the water in the basin through the large gaping sinuses on the cut surfaces of the uterine
more » ... aces of the uterine walls. I have frequently failed to inject placenta3 from the difficulty of getting them whole; but with this one, no portion of the utero-placental connexions being disturbed, I was enabled to distend it to a considerable size, and, after a long time, some of the injection oozed back through the umbilical arteries. Although I continued injecting coloured fluid for upwards of an hour, the water in the basin remained colourless, except indeed being slightly tinged with a little blood that, notwithstanding the pressure I had employed, still remained in the uterine vessels. No portion of the coloured injection passed beyond the placental vessels. This proves, or I should rather say, in deference to the experiments of others, supports the position, that no fluids by means of bloodvessels can pass from the child to the mother. I now made an opening on the external surface of the uterus, corresponding to about the centre of the placenta, and having found a large artery, I threw into it an injection, consisting. for the sake of its running freely, of a small proportion of yellow wax melted in olive oil. After injecting as much of the oil and wax as it was possible to get in, that part of the examination was left for the next day. It now occurred to me that I should like to see the uteroplacental arteries and veins, or anything else lying or passing between the placenta and uterus. On very carefully lifting the edge of the placenta, and raising its substance for a few inches from the internal face of the uterus, using at the time a powerful magnifying glass, I found that, instead of having torn through arteries and veins, leaving large open mouths, which have been supposed to be the frightful source of uterine hoemorrhage, there was really nothing of the kind to be seen. The placenta appeared to be merely in apposition with the uterine decidua, and kept there by the means already alluded to, aided probably to some extent by a very slight and imperfect stratum of cellular tissue. The uterine surface .of the placenta, covered by a thin, imperfect membrane, by some called the placental decidua, was not entirely free from marks of blood, but these were only small points, almost as few and as far between as the red points seen on making a section of the brain. I am quite aware that in the practice of midwifery we sometimes find the placenta saturated with blood, but this appearance arises from a cause which I am able to explain; and is it not an argument in favour of my views, that after ordinary labours we frequently find the uterine surface of the placenta almost as free from blood as in this case, where it had not to pass through the natural passages ? To proceed with the examination. It must be remembered that the uterine decidua as yet remained perfect. Finding a little bulging at a certain part of it, about an inch from the border of the placental attachment, I made a small incision, and immediately a portion of the injection which I had thrown in at the back of the uterus made its appearance. On the following day, the injection having hardened, I dissected the uterine substance from without to within. I found the injection in several parts, but the greater portion was deposited in lumps, about the size of filberts, on the uterine decidua. The sacculi containing the injection seemed to be formed by processes of the decidua fixed to the uterine walls, forming septa between them; they were irregular in size and form. It was one of these sacculi that I had noticed the day before, on the other side of the decidua, by its bulging appearance. In the substance of the uterus, I found that the bloodvessels lose their distinctive characters of arteries and veins from without inwards. The inner third is made up entirely of a network of sinuses, without any larger arteries and veins than those necessary for the nutrition of the parts in which they are found. These are the small vessels, or continuations of them, and therefore still smaller, that pass through the uterine decidua, the rupture of which gave rise to the points of blood seen on the uterine surface of the placenta; they are similar to the vessels of new tissues, mere minute canals, as imperfectly organized as the tissues they are intended to nourish. All this goes to prove that fluids do not pass from the mother to the child directly by-means of bloodvessels; and also that there are no utero-placental arteries and veins, the rupture of which can give rise to what we call uterine hasmorrhage. Where, then, does the blood come from? My conviction is, that when the placenta is removed, the sacculi I have spoken of become over-distended with blood, and burst; the membrane forming them is easily torn, and one after the other they give way. But by this time the outer muscular fibres of the uterus have probably contracted, which, by preventing more blood from being sent into the sinuses, and these themselves being interlaced with contractile fibres, their calibre is ohliterated, and the haemorrhage is arrested. The gush of blood which sometimes comes down upon the hand of the accoucheur, I believe arises from the sudden bursting of one of these sacculi. It is difficult to imagine that the open mouths of either arteries or veins could produce such a result. These, however, the proper bloodvessels of the uterus, are comparatively remote from the surface exposed by the removal of the placenta; they only communicate with it indirectly through the uterine sinuses, which form a supplementary and diffeteiit kind of circulation. The communication of the uterine arteries and veins with the sinuses is somewhat similar to that of the pudic arteries and veins with the corpus cavernosum. The uterine sinuses may be said to some extent to represent the same structure on a larger scale; and I believe that the uterine arteries and veins have no more to do with uterine haemorrhage from the removal of the placenta than the pudic arteries and veins would have with hemorrhage from an exposed surface proportionate in size-of the corpus cavernosum. 1 think I have shown that the mere removal of the placenta cannot possibly give rise to haemorrhage. It can only be regarded as an indirect cause of that occurrence, which, after all, is nothing more than a natural and healthy process, a disgorgement of the over-strained sinuses, and, except in a lax and unfavourable condition of the uterus, interfering but little with the general circulatory system of the mother. Formerly, I often wondered at the immense losses of blood which women sometimes sustained with impunity. Now, knowing that large portions during pregnancy are made unnecessary to the mother, and as far as regards quantity, gradually as it were removed from her system, my wonder is much diminished. Fearing I shall occupy too much space, I must leave for another occasion much that I have to say on the minute anatomy of the uterus, the microscopical appearances of the utero-placental connexions, the physiology of the placenta, and the bearings of the whole on the practice of midwifery. A short time ago I was requested to see a little girl, five years of age, who had been suffering (so the mother stated) from pain, apparently very severe, in the epigastrium. On my arrival, however, the child appeared perfectly well, and, with the exception of a furred tongue snd somewhat dry skin,
doi:10.1016/s0140-6736(02)67867-5 fatcat:lexw5c7rlvew5ci3rzkspllcjm