TlIK KKSl'li: A I loN i>K Al'I'l.KS. 87 



THE RESPIRATION OF APPLES AND ITS RELA- 

 TION TO THEIR KEEPING. 



BY FRED W. MORSE. 



The respiration of animals is a well known action and the 

 necessity for it in the living- creature is fully appreciated. 



The fact that plants and parts of plants must also 

 breathe is not so commonly understood. Yet all living 

 cells, whether a part of animal matter or vegetable matter, 

 must have oxygen to keep them alive and they give up 

 carbon dioxide and water as a result of the action of the 

 oxygen on some of their contents. Parts of plants when 

 cut off from the main stem do not die at once, and must 

 continue to breathe. This is true, whether the severed part 

 i^ a leafy branch, a fruit or a root; but some parts live 

 much longer after removal than others, and the apple con- 

 tl^.ues to breathe for many weeks after it has been picked 

 from the tree. 



The chief products of respiration are the same in plants 

 as in animals, namely carbon dioxide (commonly called 

 carbonic acid), and water. These products can be easily 

 shown by placing one or more apples in a glass jar and 

 covering it tightly. In a few hours a dewy film will cover 

 the inner surface of the jar, that in time will collect into 

 drops which will trickle to the bottom. On opening the jar, 

 a little clear lime water may be poured into it without touch- 

 ing the fruit, and the lime water will be seen to turn milky, 

 just as it will if an animal's breath is forced through it. 



The taking up of oxygen from the air can also be readily 

 shown by the following interesting experiment. 



In a large basin partially filled with water set a small 

 support on which is placed an apple and a small open dish 

 containing a solution of caustic soda or potash. The apple 

 should not touch the water nor the caustic solution. Cover 

 the support and its contents by a large bell glass or wide jar 

 with its mouth wholly in the water. Now as the apple 

 breathes in the oxygen of the air, and breathes out carbonic 

 acid, the latter will be absorbed by the caustic solution 

 while water will rise in the jar to fill the space made vacant 

 by the removal of the oxygen. Finally the water will fill 

 about one fifth of the air space originally present and re- 

 main stationary because the oxygen is all used. 



Respiration, whether in animals or in plants, causes a 



