CHAPTER 17 • WHAT MAKES THE ORGANISM A UNITY? 



1 Can a part of an animal continue to live away from the rest ? 



2 How much can an animal have removed from its body and still 



remain alive? 



3 Can any animal grow into an entirely new individual from 



one portion, as many plants can? 



4 Are there any plants that die if certain organs are removed? 



5 Can one live without a stomach? 



6 Can any of the organs be spared? 



7 If a tooth is removed, will another grow to take its place? 



8 Can any destroyed organs be regrown? 



9 If a kidney is removed, does the remaining one do double work 



or grow to double size? 

 10 When an animal dies, do all the parts die at the same time? 



Living things occur in nature as wholes, and they behave as wholes. We 

 find many thousands of distinct kinds of plants and of animals; but unless 

 something has gone wrong, there is in each case a whole fish or bird or 

 worm. We do not find, in nature, legs or eyes or clamshells, except as these 

 parts have been removed from whole organisms. When a part has been 

 removed, it no longer acts as it did when it was still with the other parts. 

 But while the parts are together, they behave in relation to one another 

 and in relation to the whole in a very distinct way, so long as there is life. 

 What makes the parts of a living thing all work together as they do ? Why 

 cannot the parts behave in the same way when they are separated? 



Why Cannot Separate Parts of Living Things Continue to Live? 



Anatomizing Life has been so hard to understand that we have felt 

 obliged to take plants and animals to pieces in order to study the organs or 

 parts. For four hundred years the study of medicine has rested on the 

 anatomy — that is, the "cutting-apart" — of the human body. We have di- 

 vided the various organs into their tissues and cells. These we have taken 

 apart chemically, to find out of what substances they consist. We have 

 carried our anatomizing so far that we often overlook the life which we 

 started out to find. 



Living Fragments Although living organisms in nature occur only as 

 wholes and act as wholes, it is possible for fragments to continue alive. We 

 all know that it is possible to remove a portion of a tree or of a worm with- 

 out killing it. And we know that the portion removed may become a whole 

 organism. If, however, the fragment does not regenerate, it dies. 



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