RESPIRATION AND FERMENTATION 



253 



leaves, are put into an insulated container, for instance a Dewar's 

 flask (Fig. 102), a rise in temperature of 30 to 40 or even 50° C. 

 may be observed. This extreme heat may eventually result in 

 death of the plant material. Still more accentuated is the rise of 

 temperature during the respiration of fungi and bacteria. On 

 damp hay, for example, there develops rapidly such a rich flora of 

 microbes, that it soon becomes very warm 

 and may "heat," if it is not scattered. 

 A considerable rise in temperature may 

 be observed also in some large flowers. 

 The flowers of Victoria regia, for instance, 

 may have a temperature 12° C. higher 

 than the surrounding air. In the inflores- 

 cences of Arum, Colocasia, and other aroids, 

 this difference can be as high as 30° C. 



Part of the energy liberated during 

 respiration may take the form of light. 

 Phosphorescence, however, is observed 

 only in the lower plants, the fungi and 

 bacteria. Their activity explains the 

 phosphorecsence of rotted wood, sea fish, 

 meat, etc. Phosphorescence, though, is 

 not always the result of respiration. It 

 may also be due simply to oxidation by 

 the air of special phosphorescing bodies of 

 protein character produced by the organ- 

 ism. 



78. Substances Consumed during Res- 

 piration. The Respiratory Coefficient. — Fig. 102. — Flask for the 



r _. „ , . . . , study of increase in temper- 



The fundamental respiratory materials, as atur e induced by respiration 

 has been seen, are the sugars, especially of germinating seeds (after 

 glucose. From the general equation of 



respiration C 6 Hi 2 6 + 60 2 -> 6C0 2 + 6H 2 0, it is clear that 

 the volume of the gases exchanged, namely, the oxygen absorbed 

 and the carbon dioxide liberated, must be equal. A plant placed 

 in a closed container therefore, does not alter the volume of 

 air, though it changes its composition, substituting carbon dioxide 

 for oxygen. In the more typical cases, the ratio of carbon dioxide 



CO* 



to oxygen in respiration, —— -, called the " respiratory coefficient," 



