JOURNAL 

 The New York Botanical Garden 



THE BREATHING OF PLANTS.* 

 There is probably no scientific question concerning which er- 



the difference between animals and plants. Ask the "average 

 man" what this difference is and he will tell you, in the first 

 place, that animals have motion while plants have not ; or, if he 

 is especially conservative, that animals have locomotion while 

 plants have not ; and, second, that plant respiration is just the 



oxygen and breathe-out carbon dioxide, while plants breathe-in 

 carbon dioxide and breathe-out oxygen." It is with the latter 

 of these " differences " that we are concerned in the following 

 paragraphs. 



By way of a gentle introduction it may be stated at once that 

 plants breathe precisely as do animals, and, second, that they do 



when we remember that, as we think more accurately, our terms 

 must be more 'carefully defined. In ordinary conversation 

 " breathing " refers to the inspiration of fresh air into the lungs, 

 and the expiration of the air that has been used. Obviously 

 plants have no lungs. We cannot sec them breathe. 



But this exchange of fresh and foul air is only incidental to 

 the real physiological process, properly termed respiration. Not 

 all animals have lungs. Earthworms, insects, jelly-fish, and 

 others may be mentioned as familiar examples of this fact. The 



