THE PROTOPLASMIC THEORY OF LIFE. 



CHAPTER I. 



INTRODUCTION, AND FLETCHER'S THEORY OF ONE ONLY 

 LIVING MATTER. 



WERE it possible even to do so in less than a volume, 

 it would be tedious and' unprofitable to go over the 

 history of all the theories of life, so I will begin at 

 the point where it became clearly apparent that all the 

 varieties of opinion might be summed up under two 

 heads 



1. Those which require the addition to ordinary 

 matter of an immaterial or spiritual essence, substance, 

 or power, general or local, whose presence is the efficient 

 cause of life ; and 



2. Those which attribute the phenomena of life 

 solely to the mode of combination of the ordinary ma- 

 terial elements of which the organism is composed 

 without the addition of any such immaterial essence, 

 power, or force. 



Up to the year 1835, the balance had been inclining 

 against the hypothesis of a vital principle, at least in 

 the crude form hitherto predominant, but the minds of 



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