CONTENTS. 



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 Eolle. The Pedigrees in the Generelle 

 Morphologic 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 Eudimentary 

 Organs. Purposelessness, or Dysteleology. Genealogy of the 

 Natural System. Chorology. ODkology. Ontogeny. Eefutation 

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

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



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-sub- 

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

 stituent 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 Amosbae. Organization and Vital Phenomena. 

 Their Movements. Amoaboid 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 VII. 



THE PEOCESSES OF EVOLUTION AND IMPEEGXATION. 



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 



