English:
A, Fertilized ova of Echinus: The male a, and the female pronucleus b, are approaching; in B they have almost fused; C, ovum of Echinus after completion of fertilization; s. n. segmentation-nucleus

Identifier: textbt00hirs (find matches)
Title: A textbook of obstetrics
Year: 1899 (1890s)
Authors: Hirst, Barton Cooke, 1861-1935
Subjects: Obstetrics
Publisher: Philadelphia : Saunders
Contributing Library: Yale University, Cushing/Whitney Medical Library
Digitizing Sponsor: Open Knowledge Commons and Yale University, Cushing/Whitney Medical Library

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the cell-contents and becomes the male pronucleus,—a small, oval body with a striated arrangement of cell-contentsabout it. Finally, the male pronucleus unites with the femalepronucleus. Conception occurs at the moment of this union, andfrom this instant dates the life-beginning of the future embryo,fetus, and infant. The Time when Coitus is Most Likely to Result in Con-ception.—Statistical studies show that impregnation is mostlikely to occur after copulation during the first eight days suc-ceeding the cessation of menstruation. There is a period, begin-ning fourteen days after the cessation of menstruation and lastingfor a week, during which coitus is least likely to be followed by 7° PREGNANCY. conception. Some regular women among my patients avoidimpregnation or become pregnant at will, by following or disre-garding this rule. As any woman, however, may ovulate at anytime during the intermenstrual period, this method of preventingconception is by no means invariably reliable.
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Fig. 59.—A, Fertilized ova of echinus : The male a, and the female pronucleusb, are approaching; in I>, they have almost fused; C, ovum of echinus after coinpletion of fertilization ; s.u., segmentation-nucleus (Hertwig). The Average Date of Conception after Marriage—Nor-mally, impregnation should succeed the first menstruationfollowing marriage, but marriages are only called sterile aftereighteen months have elapsed without conception. Pregnancyis possible, however, after years of sterility. I have had undermy care women who conceived for the first time nine, thirteen,and twenty-four years after marriage. INSEMINATION. ■ * At — 1 1 ; ; 1 °- ± . _3 ft / \ / \ 1 \ 1 \ J \ 1 \ I \ 1 \ 1 \ I \ / \ / 1 / / 1 / V 1 t \ _ / \ \ /\ / V \/\ / \ \s z r . - 1 . i 1 ■ ■ 91 - A \ \ V i i \ A \ / v Pigs. 6o and oi.—(urvrs showing relative frequencj i >f conception following coitusat different times in relation to menstruation. In both diagrams the iMn> on theab

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