STUDIES IN ANIMAL LIFE. 129 



is SO because our thoughts are not very precise on 

 tlie subject of individuality — one of the many ab- 

 stractions which remain extremely vague. To jus- 

 tify this apphcation of the word individual to every 

 distinct organ would be dif&cult in ordinary speech, 

 but ia philosophy there is ample warrant for it. 



An organ, in the physiological sense, is an instru- 

 ment whereby certain functions are performed. In 

 the morphological sense, it arises in a differem.tmtwn, 

 or setting apart, of a particular portion of the body 

 for the performance of particular functions — a group 

 of cells, instead of being an exact repetition of all 

 the other cells, takes on a difference^ and becomes 

 distinguished from the rest as an organ.* 



Combining these two meanings, we have the third 

 or philosophical sense of the word, which indicates 

 that every organ is an individual existence, depend- 

 ent more or less upon other organs for its mainte- 

 nance and activity, yet biologically distinct. I 'do 

 not mean that the heart will live independent of 

 the body — at least not for long, although it does 

 continue to live and manifest its vital activity for 

 some time after the animal's death ; and, in the 

 cold-blooded animals, even after removal from the 

 body. ISTor do I mean that the legs of an animal 

 will manifest vivacity after amputation, although 

 even the legs of a man are not dead for some time 

 after amputation; and the parts of some of the 

 lower animals are often vigorously independent. 



* See on this point what was said in our first chapter, p. 22. 

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