84 PLANT RESPIRATION 



sisted in growing the molds on various organic substances as 

 sources of carbon. After fungus mats had formed a quantita- 

 tive determination was made of the respiration of these mats, 

 first in an air current, then in a current of hydrogen and finally 

 in the air current again. This result followed with great pre- 

 cision: the fungi formed CO2 in a current of hydrogen only with 

 saccharine nutrients; on other substances not a trace of CO2 

 was liberated and the fungus mats died after a few hours of 

 anaerobiosis. On the basis of these results this author con- 

 cluded that anaerobic respiration of molds is nothing but alco- 

 hoHc fermentation which can take place only in the presence of 

 sugar. Since normal oxygen respiration proceeds vigorously 

 in the absence of sugar Diakonow assumed that anaerobic 

 respiration is an entirely independent process which has no con- 

 nection with oxygen respiration, and is to be regarded as a 

 biological adaptation. According to Diakonow the role of 

 anaerobic respiration is to supply the organism with a small 

 amount of energy which just suffices to sustain its life for a short 

 time in case of eventual anaerobiosis. It has already been 

 pointed out that the latter explanation is positively to be 

 refused. There can be no question of a biological adaptation 

 in such cases. 



In another piece of work^ Diakonow sought to obtain the 

 same results with seed-plants. He found that seeds of Vicia 

 Faha and Pisum sativum, which contain a considerable amount 

 of reserve carbohydrate, form CO2 in the presence of oxygen 

 while the seeds of Ricimis communis , which are provided with 

 only small amounts of carbohydrate, exhibit a very weak 

 anaerobic respiration. Moreover, Diakonow pointed out that 

 the seeds of Vicia Faba form more CO2 when oxygen is excluded 

 than when it is admitted. In Diakonow's opinion, this result 

 is a direct contradiction of the Pfliiger-Pfeffer theory. 



Diakonow's results with seed-plants have been confirmed by 

 Palladin' with great precision. Palladin was able to nourish 

 etiolated and green leaves of various plants with solutions of 

 organic substances. Sugar-poor, etiolated bean leaves in 



' Diakonow, N. Arch, slaves de biol. 3: 6. 1887; Ber. d. bot. Ges. 4: 411. 1886. 

 ^ Palladin, W. Rev. gen. de bot. 6: 201. 1894. 



