122 



THE EVOLUTION OF MAX. 



present position of the cell theory, and as to the views 

 commonly held in connection with it. 



FIG. 1. The human egg from the ovary of the female ; much enlarged 

 The entire egg is a simple, globular cell. The greater part of the spherical 

 egg^cell is formed by the egg-yelk, or the granular cell-substance (proto- 

 plasm), which is composed of innumerable, delicate yelk-granules, with a 

 little intervening substance. The germ-vesicle, answering to the cell- 

 kernel (nucleus) lies in the upper part of the yelk. It contains a dark 

 nucleolus or germ-spot. The globular mass of yelk is surrounded by a 

 thick transparent egg-membrane (zona pellucida, or ehoriori). This is 

 penetrated by the pore-canals, in the form of very numerous hair-like lines, 

 which run radially towards the centre of the globe ; through these the 

 thread-shaped, moving sperm-cells pass, in the process of impregnation, into 

 the egg-yelk. 



In order rightly to appreciate the Cell Theory, which 



