File:A textbook of obstetrics (1899) (14590908780).jpg

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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greater power,however, than the cilia of ordinary ciliated epithelium possess. Spermatic particles first appear in the seminal fluid at about the fifteenth or sixteenth year. There is often, in boys of twelve or thirteen, a seminal discharge, but it contains, as a rule, no spermatic particles. I have had charge, however, of a girl four- 5 Fig. 56. — Hu-man spermatozoa: A,Spermatozoon seen enface; h, head; m,middle-piece; /, tail;e, end-piece; £, C,seen from the side(after Retzius). 66 PREGNANCY teen years of age impregnated by her brother, aged thirteen, whohad stimulated his sexual development by masturbation. Sper-matozoa often disappear from the sexual discharge of old men,but the age at which this disappearance occurs varies greatly. As a general rule it might be put down as sixty-five, but it willbe remembered that the French engineer, de Lesseps, was afather at eighty-two, and that old Thomas Parr illegitimatelyimpregnated a woman after he had passed his hundredth birth-day.
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Fig- 57-—a-hj Isolated sperm cells of the rat, showing the development of thespermatozoon and the gradual transformation of the nucleus into the spermatozoonhead. In ,v, the seminal granule is being cast oil (after 11. II. Brown), i-m,Sperm-cells of an ela.smobranch ; the nucleus of each cell divides into a large numberoi daughter-nuclei, each of which becomes converted into the rod-shaped head of aspermatozoon (alter Semper). ;/, Transverse section of a ripe cell, showing the bundle of spermatozoa and the passive nucleus (/, «, after Semper). o-$t Sperma-togenesis in the earthworm; o, young sperm cell; /, the same divided into four;,/, spermatophore with the central sperm-blastophore; r, a later stage; sf nearlymature spermatozoa (after Blomfield) (from 11 addon). The Mechanism of the Ejaculation of Seminal Fluid andof its Reception within the Genital Canal of the Female.—The mechanism f ejaculation is only understood by a studyof the anatomy of tin- penis, which nerd no

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