. The science and art of midwifery. Fio. 138.—Twin placenta, showing arterial anastomosis. cal vessels explains their continued though imperfect growth and de-velopment. The blood carried to the foetus by the umbilical arteriesis returned by the umbilical vein. According to Ahlfeld,* a division may take place in the formativematerial contained within a single area germinativa. This divisionmay be complete, and thus produce separate twins inclosed in thesame amnion, which not only are of the same sex, but bear to oneanother through life the most striking similarity as regards appear- * Ahlfeld,
. The science and art of midwifery. Fio. 138.—Twin placenta, showing arterial anastomosis. cal vessels explains their continued though imperfect growth and de-velopment. The blood carried to the foetus by the umbilical arteriesis returned by the umbilical vein. According to Ahlfeld,* a division may take place in the formativematerial contained within a single area germinativa. This divisionmay be complete, and thus produce separate twins inclosed in thesame amnion, which not only are of the same sex, but bear to oneanother through life the most striking similarity as regards appear- * Ahlfeld, Die Entstehung der Doppelbildung und der bomologen Zwillinge, Arch,,f. Gynaek., Bd. ix, p. 196. 232 LABOR. ance, physical peculiarities, and both mental and moral characteris-tics ; or it may be incomplete, and thus give rise to conjoined twins,or one of the numerous forms of double monsters.*. Fig. 139.—Authors case of acardia ; the monstrosity weighed three pounds nine ounces;there were no traces of heart, lungs, pancreas, liver, spleen, or sternum. In triplets it is common to find one child derived from an inde-pendent ovum, and two from a single ovum. In a case of quadrupletsreported by P. Muller,f two ova were simple, while the third contained * Schultze, on the other hand, contends that the double monsters are derived from thefusion of two embryos developed upon the blastodermic vesicle at points close to one an-other. Schultze, Leber Zwillingsschwangerschaft,n Volkmanns Samm. klin. Vortr.,No. 34 •f P. Muller, Eine Vierlings Geburt, Ztschr. f. Geburtsh. und Gynaek., Bd. iii,p. 166. MULTIPLE PREGNANCIES AND THEIR MANAGEMENT. 233 two embryos. The children in the single ova were of the female,while those in the double ovum were of the male sex. The average weight of the individual children in multiple preg-nancies is less than that of children born single. This is par
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Keywords: ., bookcentury1800, bookdecade1890, bookidsci, booksubjectobstetrics
