What is the Use of Respiration 0 



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of the heat liberated. Had these peas been germinating and 

 respiring at the same temperatures in or on the soil, they would 

 doubtless have liberated at least as much energy in the same 

 time, but there would have been no trace of it. The heat would 

 have gone; radiation, convection, and conduction, into air and 

 soil, would have taken place. Such a transfer of heat from ger- 

 minating seeds tends to warm the surrounding soil. Whether 

 this is necessary or even desirable depends upon circumstances. 

 Seeds germinating in warm weather, in warm soil, respire more 

 rapidly and produce more heat, than seeds of the same sort ger- 

 minating at less favorable temperatures, i. e. in cooler weather 

 and cold soil. Seeds germinating in cold soil in early spring may 

 help themselves by warming their immediate surroundings with 

 the heat which they liberate and lose; but it is hard to see that 

 they benefit themselves by giving still more heat to soil already 

 warm when germinating with the temperature high and with 

 their rate of respiration correspondingly increased. 



One may determine the amount of heat required to raise 

 the temperature of the apparatus used, namely, a silvered Dewar 

 flask of 250cc. capacity, the lower quarter of the large thermom- 

 eter inserted in the flask, the 80 grams of peas and the 60 p. c. of 

 water which they absorbed while soaking for 24 hours. This 

 is, however, a tiresome task, unnecessary to describe here, and 

 we may content ourselves, at least for the time, with the knowl- 

 edge that the amount of heat required to raise the temperature 

 of this apparatus and contained peas 100 p. c. within three days 

 is large. Furthermore, this heat can not be used by the germin- 

 ating peas which liberated it in the experiments to which I have 

 referred. 



The human body is said to have a "normal temperature," 

 98.6 degrees F., 37 degrees C. This temperature is maintained 

 with slight fluctuations, so long as the body is in ordinary health. 

 Rut from the smooth surfaces of the body, heat, liberated by 

 respiration, radiates at rates which vary greatly with the circum- 

 stances. Clothing of various sorts tends to reduce radiation, 

 but although it more or less successfully does so, it does not save 

 the heat for use by the living being. The heat radiated from 

 the exposed skin of the face and hands is no more completely 

 lost to the living man than that which is held in his clothes. 



