CHAPTER VI. 



THE EGG-CELL AND THE AMCEBA- 



The Egg of Man and of other Animals is a Simple Cell. — Import and 

 Essential Principles of the Cell Theory. — Protoplasm (Cell-substance), 

 and the Nucleus (Cell-kernel), as the Two Essential Constituent Parts 

 of every Genuine Cell. — The Undifferentiated Egg-cell, compared with a 

 highly Differentiated Mind-cell or Nerve-cell of the Brain. — The Cell as 

 an Elementary Organism, or an Individual of the First Order. — The 

 Phenomena of its Life. — The Special Constitution of the Egg-cell. — 

 Yelk. — The Germ-vesicle. — The Germ-spot. — The Egg-membrane, or 

 Chorion. — Application of the Fundamental Principle of Biogeny to 

 the Egg.cell. — One-celled organisms. — The Amoebae. — Organization and 

 Vital Phenomena. — Their Movements. — Amoeboid Cells in Many-celled 

 Organisms. — Movements of such Cells, and Absorption of Solid Matter. — 

 Absorbent Blood Corpuscles. — Comparison of Amoeba with Egg-cell. — 

 Amoeboid Egg-cells of Sponges. — The Amoeba as the Common Ancestral 

 Form of Many-celled Organisms. 



" The ancestors of the higher animals must be regarded as one-celled 

 beings, similar to the Amoebae which at the present day occnr in our rivers, 

 pools, and lakes. The incontrovertible fact that each human individual 

 develops from an egg, which, in common with those of all animals, is a 

 simple cell, most clearly proves that the most remote ancestors of man 

 were primordial animals of this sort, of a form equivalent to a simple cell. 

 When, therefore, the theory of the animal descent of man is condemned as 

 a 'horrible, shocking, and immoral' doctrine, the unalterable fact, which 

 can be proved at any moment under the microscope, that the human egg 



