BOOK III. 



THE CHARACTERS COMMON TO LIVING BEINGS. 



Chapter I. Summary: The doctrine of vital unity. Chapter II. 

 The morphological unity of living beings. Chapter III. 

 The chemical unity of living beings. Chapter IV. The 

 mutability of living beings. Chapter V. The specific 

 form, its acquisition, and reparation. Chapter VI. Nutri- 

 tion. 



CHAPTER I. 



THE DOCTRINE OF VITAL UNITY. 



Phenomena common to all living beings Theory of vital 

 duality Unity in the formation of immediate principles 

 Unity in the digestive acts The common vital fund. 



WHEN we ask the various philosophical schools what 

 life is, some show us a chemical retort, and others 

 show us a soul. Whether vitalists or of the mechanical 

 school, these are the adversaries who since philosophy 

 began have vainly contested the possession of the 

 secret of life. We need not concern ourselves with this 

 eternal quarrel. We need not ask Pythagoras, Plato, 

 Aristotle, Hippocrates, Paracelsus, Van Helmont, 

 and Stahl what idea they formed of the vital 

 principle ; nor need we probe to the depths the 

 ideas of living nature held by Epicurus, Democritus, 

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