CHAPTER I 



MATTER AND CELLS 



1. Living and Lifeless Matter. What matter is we are 

 not yet able to say, but as it exists in our world it may be 

 separated into two great divisions, living matter and 

 lifeless matter. So far as present knowledge goes, these 

 two sorts of matter are wholly distinct the one from the 

 other, and lifeless matter never becomes living matter 

 except under the influence of matter already living. The 

 same substances are indeed found in the two sorts of 

 matter, and when living matter is killed, or becomes life- 

 less, no change can be discovered in its weight. That 

 mysterious something called life is therefore not material, 

 and living matter may be said to be only ordinary lifeless 

 matter existing in a different state or condition. 



2. Chemical Elements. A substance ;^}ich-8ajirjci;,b^ 

 divided into two or more different kinds of matter is 

 called a chemical element, or a simple substance. All 

 others are called compound substances. Matter is sepa- 

 rated into its elements by processes which affect the mole- 

 cules or the atoms of which it is composed, that is, by 

 chemical analysis. 



A molecule may be denned as the smallest particle of 

 matter which exists alone and retains most of the proper- 

 ties of the mass of the substance. An atom is one of the 

 ultimate particles of which a molecule is composed The 



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