78 THE BEGINNINGS OF LIFE. 



under the abstract name c Life/ We must not be 

 blinded, however, by the use of such a word we must 

 not fall into the old error of supposing that because by 

 a process of generalization we have conceived a mere 

 abstract notion which we name c Life/ that, therefore, 

 there is anything existing, of and by itself, answering 

 to this term. No, each material body has properties of 

 its own properties which are due to its molecular con- 

 stitution and which make it what we know it to be. 

 These properties are, however, often classed together 

 in a definite way; certain of the objects around us, for 

 instance, have a power of growing, of developing, and 

 of reproducing their kind. Bodies possessing such pro- 

 perties have been arbitrarily named c Living ' bodies, 

 and the word c Life ' has been used as a mental symbol 

 connoting the sum total of the properties which dis- 

 tinguish such an aggregate from the member of the 

 other great class whose representatives do not present 

 such properties. These properties may be looked upon 

 as of a higher and more subtle nature, but it should be 

 distinctly understood that they are as much dependent 

 upon the mere qualities and nature of the material 

 aggregate which displays them, as the properties of a 

 metal or the properties of a crystal are the results of 

 the nature and mode of collocation of the atoms of 

 which these bodies are composed. Hence in using the 

 phrase c Genesis of Life, 3 it must not be supposed that 

 we should,, in so doing, refer to the actual origination 

 of any c principle ' or c force' that did not pre-exist; 



