XViil CONTENTS. 



CHAPTER Y. 



ON PERIODICAL OVULATION, AND THE FUNCTION OF MENSTRUATION. 



PAGE 



PERIODICAL OVULATION Pre-existence of eggs in the ovaries of all animals 

 Their increased development at the period of puberty Their successive 

 ripening and periodical discharge Discharge of eggs independently of sexual 

 intercourse Rupture of Graafian follicle, and expulsion of the egg Pheno- 

 mena of oestruation MENSTRUATION Correspondence of menstrual periods 

 with periods of ovulation in the lower animals Discharge of egg during 

 menstrual period Conditions of its impregnation, after leaving the ovary 



563-575 



CHAPTER VI. 



ON THE CORPUS LUTEUM OF MENSTRUATION AND PREGNANCY. 



CORPUS LUTEUM OF MENSTRUATION Discharge of blood into the ruptured Graafian 

 follicle Decolorization of the clot, and hypertrophy of the membrane of the 

 vesicle Corpus luteum of menstruation, at the end of three weeks Yellow 

 coloration of convoluted wall Corpus luteum of menstruation at the end 

 of four weeks Shrivelling and condensation of its tissues Its condition at 

 the end of nine weeks Its final atrophy and disappearance CORPUS LUTEUM 

 OF PREGNANCY Its continued development after the third week Appearance 

 at the end of second month Of fourth month At the termination of preg- 

 nancy Its atrophy and disappearance after delivery Distinctive characters 

 of corpora lutea of menstruation and pregnancy . . . 576-585 



CHAPTER VII. 



ON THE DEVELOPMENT OF THE IMPREGNATED EGG. 



Segmentation of the vitellus Formation of blastodermic membrane Two 

 layers of blastodermic membrane Thickening of external layer Formation 

 of primitive trace Dorsal plates Abdominal plates Closure of dorsal and 

 abdominal plates on the median line Formation of intestine Of mouth 

 and anus Of organs of locomotion Continued development of organs, after 

 leaving the egg . . . . . . . . 586-595 



CHAPTER VIII. 



THE UMBILICAL VESICLE. 



Separation of vitelline sac into two cavities Closure of abdominal walls, and 

 formation of umbilical vesicle in fish Mode of its disappearance after hatch- 

 ing Umbilical vesicle in human embryo Formation and growth of pedicle 

 Disappearance of umbilical vesicle during embryonic life . . 596-598 



