CONTENTS. VI 1 



PAGE 



Formation of the primitive groove and laminje dorsales . . . . . . 83 



amnion . . . . . . . . . . . . 85 



umbilical vesicle . . . . . . . . . . 85 



Formation of the allantois . . . . . . . . . . . . 86 



i. In the human subject . . . . . . . . . . . . 88 



Development and office of the allantois . . . . . . . . 88 



of the amnion . . . . . . . . . . . . 90 



chorion . . . . . . . . . . . . 90 



Formation and structure of the decidua . . . . . . . . 90 



Description of the uterine glands . . . . . . . . . . 91 



Formation and structure of the placenta . . . . . . . . 93 



c. Development of organs .. .. .. .. .. .. 96 



a. Development of the vertebral column and cranium . . . . . . 96 



chorda dorsalis' .. .. .. .. .. 96 



vertebral column . . . . . . . . . . 98 



b. Development of the vascular system .. .. .. v. .. 99 



Formation of the heart . . . . . . . . . . . . 99 



Transformation of the aortic arches . . . . . . . . . . 1 00 



Development of veins .. .. .. .. .. .. JOO 



of blood-vessels generally .. .. .. .. 101 



of lymphatics .. .. .. .. .. .. 105 



c. Development of the nervous system . . . . . . . . . . 106 



First traces of the nervous system . . . . . . . . . . 106 



Development of cerebral hemispheres .. .. .. .. .. 107 



d. Development of the alimentary canal .. .. .. .. .. 107 



e. Development of the respiratory apparatus . . . . . . . . ] 09 



The thymus gland .. .. .. .. .. _ JQQ 



f. Development of the Wolffian bodies, urinary apparatus, and sexual organs .. 110 



Wolffian bodies, formation of, and connections .. .. .. .. no 



Ovaries and testes .. .. .. .. .. jU 



Existence of a rudimentary uterus in the male .. .. .. .. m 



D. Development of the animal tissues .. .. .. .. .. 113 



Theory of development from cells .. .. .. .. UQ 



Nature and composition of the several parts of a cell . . . . . . 113 



Modes of development of cells .. .. .. .. .. jjg 



' of multiplication .. .. .. . . .. joo 



Transformation of cells in the development of tissues . . . . . . 123 



of nuclei . . . . . . . . . . 125 



Importance of nuclei . . . . . . . . . . 125 



Development of the blood . . . . . . . . 127 



In the embryo . . . . . . . . < ^ 127 



In the adult . . . . . . . . 1 32 



