A human embryonic vesicle showing placenta formation / by John M. Swan ... from the pathological laboratory of St. Mary's Hospital.

  • Swan, John M. (John Mumford), 1870-1949
Date:
1904
Catalogue details

Licence: In copyright

Credit: A human embryonic vesicle showing placenta formation / by John M. Swan ... from the pathological laboratory of St. Mary's Hospital. Source: Wellcome Collection.

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    Extracted from The American Journal of the Medical Sciences, March, 1904. A HUMAN EMBRYONIC VESICLE SHOWING PLACENTA FORMATION. By John M. Swan, M.D., PATHOLOGIST TO ST. MARy’s HOSPITAL, PHILADELPHIA. (From the Pathological Laboratory of St. Mary’s Hospital.) The specimen from which the sections exhibited were taken was given to me in the laboratory of St. Mary’s Hospital in June, 1903, by Dr. D. F. Harbridge. It had been passed from the vagina of one of his patients about June 16th. After the passage of the speci¬ men the patient had profuse hemorrhage for a week, and had fainted on account of the loss of blood. On November 17, 1902, the woman had been in a trolley accident, and six days later she had a miscarriage. The product of concep¬ tion was estimated by Dr. Harbridge to be between the sixth week and the second month of development. Since this miscarriage the patient’s menstrual periods had been irregular and the flow had been profuse. The specimen was a spherical, fleshy mass, brown in color, about 0.5 cm. in diameter. On section it was found to contain a cavity, which was lined by a membrane that resembled amnion in appear¬ ance. Microscopically this membrane proved to be chorion, with its villi projecting into the maternal blood spaces and bathed in the maternal blood. The villi are seen to be composed of fetal meso¬ derm, which is limited by two layers of tissue: first, a layer of dis¬ tinctly outlined columnar cells, each containing an oval nucleus; and second, a continuous layer of cytoplasm containing irregular nuclei, but showing no demarcation into cell areas. The former of these layers, known as the layer of Langhans, is formed of the fetal ectoblastic cells, which are the remains of the trophoblast; and the latter is the syncytium, a descendant of the trophoblast. The tissue at the periphery of the section is the decidua placen- talis, and shows the dilated vessels which ramify in it. The earliest recorded human placenta that has been examined is that described by H. Peters, of Vienna, in 1899. The following is a brief resume of Peters’ conclusions, after studying the appearances of the developing embryonic vesicle, which he estimated to be four days’ old: