OXYGEN RESPIRATION II 



because carbohydrate is changed into fat, whereat a certain 

 amount of oxygen is set free. Accordingly the absorption of 

 atmospheric oxygen for respiration must decrease, since a part 

 of the carbon compounds are oxidised to CO2 by the oxygen 



left from the fat formation. ^ 



COo 



For experimental studies of -^^r^' the rapidly growing and 



U2 



energetically respiring molds are very suitable. Studies carried 



out with them have proven that the respiratory quotient is not 



exactly the same for various sources of carbon.- With the 



very abundant respiration of Aspergillus niger, the expected 



CO 

 theoretical values of x^ for various organic nutrients can be 



established analytically.^ 



On the basis of this e\'idence we may conclude that the heat 

 production of respiration may not always be traced to a direct 



, COo . 



combustion of sugar. This is permissible only when ^- is 



COo 



equal to i. while ^ ' > i indicates a lower heating effect. As 



to what a value less than i indicates, no defmite conclusion is 

 possible since the low value of the respiratory quotient can 

 depend upon various conditions. If complete combustion of an 

 oxygen poor respiratory material (such as fat) takes place the 

 heating effect is, of course, very great but if only an oxygen- 

 tying action, which does not result in complete combustion, 

 is involved, the heating effect in such cases remains small. 



Unfortunately the formation of water in plant respiration 

 has been insufficiently studied. This is all the more to be 

 regretted since the amount of water formation in many cases 

 can serve as a criterion of a complete combustion of respiratory 

 material. Direct analytical determinations of the water 

 formed in respiratory processes are to be found in the older work 

 of N. Liaskowski,"^ yet the question of water formation in 



1 Godlewski, E. loc. cit. 



2Diakonow, N. Ber. d. bot. Ges. 5 : nS- 1887; Puriewitsch, K. Jahrb. f. wiss. Bot. 



35: 573- 1900. 



3 Kostytschew, S. Jahrb. f. wiss. Bot. 40: 563- 1904. 



« Liaskowski, N. /oc. a7.,- c/. also Landwirtschaft. Versuchs-Stationen 17:219. 1874- 

 [For a brief description of the experiments of Liaskowski see Palladin's Plant Physiology 

 (trans, by Livingston) 3rd ed.. p. 220-221.] 



