THE DOCTRINE OF VITAL UNITY. I47 



Boerhaave, Willis, and Lamettrie ; nor need we 

 apply to the iatromechanicians nor to the chemists. 

 We may do better than that. We may ask nature 

 itself. 



Phenomena Common to Living Beings. — Nature 

 shows us an infinite number of beings, animal or 

 vegetable, described in ordinary language as living 

 beings. This language implicitly assumes something 

 common to them all, a universal manner of being 

 which belongs to them without distinction, without 

 regard to differences of species, types, or kingdoms. 

 On the other hand, anatomical analysis teaches us 

 that animated beings and plants may be divided into 

 parts ever decreasing in complexity, of which the 

 last and the simplest is the anatomical element, the 

 cell, the microscopic organic unit which,-too, is alive. 

 Common opinion suspects that all these beings, 

 whether entire as in the case of animal and vege- 

 table individuals, or fragmentary as in the case of 

 cellular elements, have the same manner of being, 

 and present the same body of common characteristics 

 which rightly gives them this unmistakable title of 

 living beings. Life then essentially would be this 

 manner of being, common to animals, vegetables, and 

 their elements. To seize in isolation these common, 

 necessary, and permanent features, and then to 

 synthetize them into a whole, will be the really 

 scientific method of defining life, and of explaining 

 its nature. 



And here then immediately arises a fundamental 

 question which gives one pause, a question of fact 

 which must be solved before we can go further. 

 Is there really a common manner of being in all 

 these things ? Are animal life^ vegetable life, and the 



