EXERCISE 109 -DEMONSTRATION 



When part of a plant or of an animal is cut off, in some cases the surface merely heals up, while 

 other cases the whole of the missing part is regrown. 

 Problem. How much can be regrown if half of a worm is cut off ? ' 

 What to use. A live earthworm or a live Planaria (flatworm) ; sharp knife or scissors. 

 What to do. Cut the animal into two close to the middle, and return to earth or water for further 

 )servation. 



Record. Describe the response of the animal to the section, and the changes to be noted from 

 ime to time say at intervals of two days. Make drawings showing what happened to each part, as 

 well as the appearance of the worm before the operation. 



Questions. 1. What practical use can be made of the fact that organisms can regrow removed parts? 

 2. What is the difference between the regeneration of roots on a slip or cutting and the formation 

 )f a new plant from a bulb or tuber ? 



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