GENERAL IDEAS OF LIFE. 55 



and Plants. From this point of view each being is 

 distinguished from another being as a given individual 

 and as a particular species; but all are in some way 

 alike and thus resemble one another: common life, 

 elementary life, the essential phenomena of life; it is 

 life itself} 



The manifestations of life may therefore be regarded 

 from the point of view of what is most general among 

 them. As we go down the scale of anatomical organ- 

 ization, as we pass from apparatus (circulatory, 

 digestive, respiratory, nervous) to the organs which 

 compose them, from the organs to the tissues, and 

 finally from the tissues to the anatomical elements or 

 cells of which they are formed, we approach that 

 common, physiological dynamism which is elementary 

 life^ but we do not actually reach it. The cell, the 

 anatomical element, is still a complicated structure. 

 The elementary fact is further from us and lower 

 down. It is in the living matter, in the molecule of 

 this matter, and there we must seek it. 



Galen gave in days gone by as the object of 

 researches on life, the knowledge of the use of the 

 different organs of the animal machine; "de usu 

 partium." Later, Bichat assigned to them as their 

 end the determination of the properties of tissues. 

 Modern anatomists and zoologists try to reach the 

 constituent element of these tissues — the cell. Their 

 dream is to construct a cellular physiology, ?ii physio- 

 logical cytology ; but we must go further than that. 



^ Le Dantec has objected to this conception of phenomena 

 common to different hving beings. He insists that all 

 phenomena which take place in a given living being are 

 proper to him, and differ, however slightly, from those of 

 another individual. The objection is more specious than real, 



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