Gynecology . from an unfertilized ovum. Chief among these are the appearance of these tumors in parts of the body far distant from the ovary, and also their development in men not only in the testis, but in other parts of the body. Further, the structure of the tissues NEW GROWTHS 347 of a dermoid corresponds in a general way to the age of the patient who carries it. Also theabsence of fetal membranes, which normally are developed before any of the other tissues foundin dermoids, contradicts the theory of origin from an unfertilized egg. Finally, if it were possible for a dermoid to spring fro
Gynecology . from an unfertilized ovum. Chief among these are the appearance of these tumors in parts of the body far distant from the ovary, and also their development in men not only in the testis, but in other parts of the body. Further, the structure of the tissues NEW GROWTHS 347 of a dermoid corresponds in a general way to the age of the patient who carries it. Also theabsence of fetal membranes, which normally are developed before any of the other tissues foundin dermoids, contradicts the theory of origin from an unfertilized egg. Finally, if it were possible for a dermoid to spring from an unimpregnated egg one wouldexpect a much greater frequency of these tumors, considering the enormous number of unfertil-ized eggs that pass the tube. Nevertheless, only 5 authentic cases of dermoids in the tubeshave been reported. Since the dermoids and teratomata contain constituents from all three germinal layers(entoderm, ectoderm, mesoderm), it must be that they spring from cells that stand close to. Fig. 146.—Colloid Carcinoma of the power of the section shown in the previous drawing. This shows the typical cylindricepithelium associated with the large intestine. The epithelium has fallen out of many of the glands,leaving spaces. the fertilized ovum. This requirement is met by the so-called blastomeres, which are theproducts of the first cell division of the impregnated egg, and which experimentation on thelower animals has shown have, when isolated, the power of producing rudimentary is readily conceivable that in the complicated processes of growth of the earliest embryonaltime some of these cells may be displaced to the most diversified parts of the developing organ-ism. It has been proved by animal experimentation that the earliest segmentation divides theovum into two kinds of blastomeres, those which become the later germ-cells (ova or spermato- 348 GYNECOLOGY zoa) and those which enter into the construction of the body (somatic cells). I
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