372 CHANGES OF ORGANIC MATTER IN THE PLANT. 



number of carbon affinities for oxygen had been satisfied in 

 each case, and would in no way indicate from whence the supply 

 of oxygen came. And in case free oxygen was active in normal 

 respiration, in intramolecular respiration, when free oxygen was 

 absent, its full supply might still be obtained through constant 

 powerful attractive forces which could take oxygen from other 

 combinations and thus give rise to secondary changes." 



984. Eriksson l has shown^that a slight elevation of tempera- 

 ture occurs during intramolecular respiration, amounting in the 

 case of a mass of seedlings, flowers, or fruits, 125 cc. in bulk, 

 to .l-.3 C. In the experiments which he made with yeast, he 

 obtained a much larger increase of temperature. Thus, when he 

 employed 500 cc. of a fluid containing five parts b}- weight of 

 water and one part by weight of yeast, together with 10 per cent 

 of sugar, he obtained an increase of 3. 9 C. He found, further, 

 that in intramolecular respiration, both in the case of germina- 

 tion and in that of yeast, the elevation of temperature can be 

 noticed for one week. After this time, with diminution of the 

 respiration, the temperature becomes the same as the surround- 

 ing air ; but even then life is not extinct. 



985. The curious experiment of introducing the smallest pos- 

 sible amount of organized ferment into a liquid from which all 

 air has been expelled, but which is otherwise fitted to undergo 

 fermentation or putrefaction, has resulted in setting up one or 

 the other of these processes, and causing the liberation of con- 

 siderabje quantities of carbonic acid. It is believed that in this 

 case likewise the needed oxygen is supplied bj* that in the mole- 

 cules of ox3*gen-compounds, which are easily broken down. 



986. While the non-nitrogenous compounds are those which 

 play the most important part in furnishing material for oxidation 

 and the release of energy, the nitrogenous matters share in this 

 activity. Some physiologists 2 look upon the latter as the chief 

 matters concerned in the process of respiration, and would regard 

 the non-nitrogenous compounds as merely supplying waste. Ac- 

 cording to this view, asparagin is a waste product somewhat 

 analogous to urea in animal economy. 



987. From what has been said, it is plain that respiration does 

 not consist merely in the direct absorption of oxygen and the 

 immediate oxidation of compounds within the organism, but 

 that it is a complicated process of which the absorption of oxy- 

 gen and the evolution of carbonic acid are the extreme terms. 



1 Untersuchungen aus dem bot. Inst. zu Tubingen, 1881, p. 105. 

 8 Borodin : Botanische Zeitung, 1878. 



