vlii CONTENTS. 



PAC.B 



parison of Artificial with Natural Conditions of Breeding. The 

 Struggle for Existence. Necessary Application of the Theory of 

 Descent to Man. Descent of Man from the Ape. Thomas Hux- 

 ley. Karl Vogt. Friedrich Kolle. The Pedigrees in the Generelle 

 Morphologie and the " History of Creation." The Genealogical 

 Alternative. The Descent of Man from Apes deduced from the 

 Theory of Descent. The Theory of Descent as the Greatest Induc- 

 tive Law of Biology. Foundation of this Induction. Palaeon- 

 tology. Comparative Anatomy. The Theory of Rudimentary 

 Organs. Purposelessness, or Dysteleology. Genealogy of the 

 Natural System. Chorology. ffikology. Ontogeny. Refutation 

 of the Dogma of Species. The " Monograph on the Chalk 

 Spongea ;" Analytic Evidence for the Theory of Descent ... 93 



CHAPTER VI. 



THE EGG-CELL AND THE AMOEBA. 



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

 Essential Principles of the Cell Theory. Protoplasm (Cell-snb- 

 stance), and the Nucleus (Cell-kernel), as the Two Essential Con- 

 stitnent 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 Indi- 

 vidual 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. Absor- 

 bent Blood Corpuscles. Comparison of Amoeba with Egg-cell. 

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

 Ancestral Form of Many-celled Organisms ... ... ... 120 



CHAPTER VIL 



THE PROCESSES OF EVOLUTION AND IMPREGNATION. 



Development of the Many-celled from the One-celled Organism. The 

 Cell-hermit and the Cell-state. The Principles of the Formation 

 of the State. The Differentiation of the Individuals as the 



