The first was reported in 1854 by Hiffelsheim and Laboulbene, after that of Ch. Robin, who maintained that these lesions are independent of each other, although sometimes coinciding. He held that obliteration of a few placental vessels or of a cotyledon may modify the whole pla cental circulation and thus cause hemorrhage, but that the lesion itself is independent of the hemorrhage.
Laboulbene and Hiffelsheim came to the following conclusions: 1. There may be, at the same time, apoplexy and obliteration of villi; 2. Apoplexy does not cause obliteration, but rather the reverse; 3. The two lesions are independent of each other.
The appearance of the diseased cotyledons has sometimes been wrongly attributed to retrogressive changes in coagula about which the authors do not agree.
Jacquemier says that the serum is reabsorbed, while the coagulum grows dense by contraction. The pigment gradually disappears, being first lost at the circumference, unless the clot has been formed by succes sive additions. Sometimes the coagulum is so changed as to be unrec ognizable or to simulat,e cartilage, cancerous growths or tubercles, nodu lar or diffuse.
Sometimes the coagula enclose cavities containing blood, and sometimes they are soft like adipose tissue and seem to be encysted. Often the um bilical vessels penetrating the coagula are obliterated. When the blood clot is large, the placental tissue is firm and white around them, and one. or more lobes of the placenta are obliterated.
When the hemorrhage has led to detachment of the placenta, the circu lation cannot be restored. If, however, the extravasation is small, the blood may be taken up and the serotina reproduced. The latter then has new vessels, adherence between the placenta and uterus is not disturbed, and the umbilical circulation is not suspended.
Ch. Robin states that fibrin appears in two forms, according to the man ner of its coagulation. The first is the thrombus, formed while the blood is still circulating, as in the case of cardiac vegetations and in aneurisms. The thrombus is stratified and pale in color, and may look like organized tissue, but never has fasciculi as does fibrous tissue. It has no capillaries and never grows, but either enlarges by the deposition of new laminte, or becomes granular and is reabsorbed. Now, it is not even this form of fibrin which is found in the placental coagula.
The second form of fibrin, called a clot, is produced during life, when extravasation, apoplectic or otherwise, takes place, or when the current of blood in some normal or pathological cavity is interrupted. The clot, proper, is formed of fibrin and red and white corpuscles, is softer than a thrombus, is friable and non-striated.
These are the coagula found in the placentit, and some writers speak of their organization because the fibrin resembles formed connective tissue. Vertlier states that coagula may either contract and become permanent, be destroyed or become organized. The contraction and permanence of eoagula is simple and undisputable. The destruction of the clot consists in several stages. The fibrin, when first deposited, gives a yellowish, lardaceous look, and a firm yet friable feeling. It soon, however, becomes granular and presents two kinds of granules. One kind is proteid, dis solving in alkalies and in acetic acid, the other fatty, resisting these re agents. The mass then becomes soft and liquid, resembling pus, and regarded as such by earlier writers. In these pyoid masses one finds, 1, innumerable fibrinous and fatty g-ranules; 2, some liquid; 3, fatty white corpuscles; 4, granular bodies formed either by simple adhesion of fatty molecules or by their accumulation in a white corpuscle; 5, hematoidin crystals.
It was once held.that the clots could become organized.
Hunter's theory of organizable plastic lymph was soon abandoned. Cruveilhier denied that coagula are organized, and 80 did Robin, but Vul pian reaffirmed the old theory, and Weber describes the organization of extravasated blood. In the coagula of ligated vessels the white corpuscles, in a few days, change their shape, the nuclei divide, they send out slen der prolongations and form a reticulum like that of connective tissue. Then capillaries form and anastomose with neighboring vessels, the red corpuscles disappearing.
Bustamente, adopting Dalton's ideas, says that the villi, with their arterial and venous channels, plunge int,o the maternal blood from which they are not separated at all. The placen'ta, according to him, is contin ually bathed in the mother's blood, which extends into the interstices of the cotyledons like liquid into a sponge.