. A study of the causes underlying the origin of human monsters : third contribution to the study of the pathology of human embryos . ble quantity of magma reticule,which I did not remove, and therefore could not obtain goodcamera drawings. The portion of the chorion to which thevesicle is attached was cut out and stained with alum cochinealand cleared in oil, but even after this treatment it was impos-sible to obtain any clear picture. The specimen was nextimbedded in paraffin and cut into sections 10 microns series proved to be perfect. From the sections a recon-struction was made
. A study of the causes underlying the origin of human monsters : third contribution to the study of the pathology of human embryos . ble quantity of magma reticule,which I did not remove, and therefore could not obtain goodcamera drawings. The portion of the chorion to which thevesicle is attached was cut out and stained with alum cochinealand cleared in oil, but even after this treatment it was impos-sible to obtain any clear picture. The specimen was nextimbedded in paraffin and cut into sections 10 microns series proved to be perfect. From the sections a recon-struction was made in wax. The dimensions of the different portions of the vesicle areas follows: No. i.] ORIGIN OF HUMAN MONSTERS. 147 Diameter of stem . mm. Length of stem Length of vesicle Width of vesicle Length of invagination Width of invagination Diameter of opening of The sections and reconstruction show that the embryonicvesicle is attached to the chorion by means of a stem. Thegreater part of the vesicle itself is composed of two layers,ectoderm and mesoderm. In the neighborhood of the em-. Fig. 1 id.—Section through the stem uniting the umbilical vesicle withthe chorion. X 50 times. The cavity within the stem lined withepithelium is the allantois. bryonic stem there is a third outer layer which shows all ofthe characteristics of the ectoderm. Just beside the attach-ment of the vesicle to the stem there is a sharp, deep andnarrow invagination of all three embryonic the stem there is a sharply defined allantois whichcommunicates with the cavity of the vesicle just below thecavity of the ectoderm. The ectodermal plate of the invagi-nation is very broad but not of equal thickness throughoutits whole extent. It extends to the outside of the vesicle andends quite abruptly in the neighborhood of the stem. Theblood-vessels of the mesodermal layer extend to the stem butdo not enter it, nor are there any blood-vessels in the chorio
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectcon, booksubjectfetus
