According to Crede, these bands are necessarily 'found in the third or fourth weeks of fcetal development, or before the closure of the ventral cavity; for, in admitting inflammation, it is only possible to affect those parts still projecting. Ordinarily, however, it is in the deep part, or in their neighborhood, that the amnion is adherent. And, moreover, one never sees those ulcerations, capable of traversing the abdominal integu ment, and even of the bone, in cases of tuberculosis, scrofula, rachitis, syphilis, etc. It is later, in the eighth week, that these lesions are pro duced. In the second month the fcetns is separated from the amnion by a notable quantity of liquid, and the amnion adheres to the chonon. It is, therefore, before this that they are produced, that is, towards the time of formation of the amnion, the third week. Another proof is the differ ence that exists between the amnion and the skin of the fcetns. From the eighth week the fcetus has its epidermic covering, and this cannot fur ther proliferate. In the third, on the contrary, the amnion is developed, and tends to blend towards the middle of the back of the fcetus, and its folds, before they unite, form an acute angle; and he believes that the ex aggeration of the amniotic fold becomes the origin of the premature formation of cells and nuclei, which, manifesting themselves on each side, induce premature fusion of the two amniotic folds. If. on the other hand, one remembers that Reichert and Remak consider the amnion as composed of two layers, one epidermic, in connection with the skin of the embryo, the other in immediate continuation with the cutaneous layer, one understands that the folds are able by their traction to cause the flexion of the fcetus and help to give it its form. Braun finds the cause
of this adhesion in the too little quantity of fluid, or the too tardy sepa ration of the amnion, and in concussion of the fcetus, which forces it to lengthen, instead of remaining bent. (Stadhagen.) Crede depending on the researches of Panum, of Dareste, believes in the influence of the variations of temperature and variations of pressure in the uterine con tractions, and the sudden va,so-motor disorders, produced in the uterus by the emotions and physical influences.
What is the relation between monstrosities and these amniotic bands? Crede, out of 109 cases of monstrosities, has found 69 of them with amniotic bands, and 21 with hernim cerebri, eventrations, spontaneous amputations, and atrophies of the bones. The opinion of Braiin, who thinks that the spontaneous amputations are produced more frequently in the upper than the lower extremity, because the upper are more prominent, is not sustained by Crede's eases. On the other hand, amni otic adhesions are more common in the upper extremity. Out of 11 cases, 7 were of the upper extremity. All agree that the spontaneous amputations are due to the amniotic bands.