A text-book of embryology for students of medicine / by John Clement Heisler.

  • Heisler, John Clement.
Date:
1907
Catalogue details

Licence: In copyright

Credit: A text-book of embryology for students of medicine / by John Clement Heisler. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    occupies nine calendar months or about ten lunar months— that is, from 273 to 280 days. The period of human gesta- tion is arbitrarily divided by His into three stages: (1) The 2 Fig. 1.—1 to 8, Various stages of the development of the spermatozoon of the mouse ; 9, the spermatozoon of the mouse (after F. Hermann); 10 and 11, spermato- zoa of the dog; 10, as seen from the side ; 11, as seen from the broader surface (after Bonnet). stage of the ovum, comprising the first two weeks of develop- ment ; (2) The stage of the embryo, extending from the end of the second week to the fifth week, during which time the germ begins to assume definite form; and (3) The stage of