THE HUMAN EGG-CELL. 121 



is a simple cell, whicli is in no -way different to those of other mammals, 

 must equally be pronounced ' horrible, shockiDg', and immoral.' " — Stamm- 

 BAUII DES Menschengescdlechts (1870.) 



In order clearly to understand Ontogeny, or the evolution 

 of the individual Man, the most significant of the many 

 wonderful and varied facts which meet us must first 

 be brought into prominence, and then from the important 

 points of view thus gained, the innumerable less weighty 

 and important phenomena must be explained. The first 

 and most important point of view, and, therefore, the 

 starting-point of our ontogenetic studies, is the fact that 

 every human individual is developed from an entirely 

 simple cellular egg. The human egg-cell is, in its whole 

 form and constitution, not essentially difierent from those 

 of other Mammals, though there is some difference between 

 the egg-cells of Mammals and those of other animals. 



This most important fact, the fundamental significance 

 of which is hardly surpassed by any other, is of recent 

 discovery. It was only in 1827 that Baer, by practical 

 observation, discovered the human and mammalian egg. 

 Before that, the larger vesicles, which in reality contain the 

 true and much smaller egg, had been erroneously regarded 

 as the eggs. Of course the important discovery that the 

 mammalian egg is a simple cell like that of other animals 

 could only be made after the establishment of the Cell 

 Theory, which was first laid down, with respect to plants, 

 by Schleiden, and extended to the animal kingdom by 

 Schwann in 1838. The reader is already aware of the 

 great importance of the Cell Theory in the complete ex- 

 planation of the human organism and its evolution. It 

 therefore seems desirable to say a few words as to the 



