266 THEORETICAL CONSIDERATIONS 



cule," accompanied by a rearrangement of oxygen within the mole- 

 cule. By these processes, by which the necessary kinetic energy is 

 secured for the maintenance of life, CO^ and alcohol are split off, so 

 that there arise within the " living molecule" reduced atom-groups, 

 which have a great affinity for oxygen. In aerobic respiration there 

 is no possibility for these reduced atom-groups (alcohol) to become 

 fixed by the taking in of oxygen, therefore the alcohol is given off 

 in addition to carbon dioxide. When oxygen is plentifully present, 

 as in aerobic respiration, the alcohol in the nascent state is so com- 

 bined that, under the influence of oxygen it serves for the formation 

 of new parts of living protoplasm, through the agency of the oxydases 

 of the air. 



Maximow's ^" experiments harmonize with the essential identity 

 of aerobic and anaerobic respiration. He found that sap, expressed 

 from mycelium of Aspergillus nige?', showed, on standing, a gaseous 

 exchange analogous to that of normal respiration. This exchange 

 was found to result from the activity of enzymes in the sap, inde- 

 pendently of each other, and causing, the one an absorption of COg, 

 the other a giving off of oxygen. The first is similar to zymase, the 

 second belongs to the group of the oxydases. The enzyme which 

 splits off CO2 acts, as does Buchner's zymase (alcoholase), equally 

 energetically in air and in hydrogen. 



In April, 1908, Palladin'^'^^ published the results of his investiga- 

 tions on the respiration-pigment in plants, detected several years 

 ago by Schonbein^* and later studied by Reinke.^^ Palladin con- 

 sidered that the physiological significance of these pigments is iden- 

 tical with that of the haemoglobin of the blood, and proposed for 

 them the generic term " phytohaematin." It is the role of these 

 substances to receive the oxygen from the air through the intermedia- 

 tion of the oxidases of respiration, and pass it on to the catalases and 

 reductases. He gives the following diagram to illustrate, not only 



Secondary processes 



Atmospheric oxygen 

 Primary processes I 



i i , , 



Anaerobic enzymes (zymase, etc.) Oxydases of respiration 



Katalase, reductase < Phytohaematin 



Fermentation products ^ Respiration products 



(Alcohol and other substances) (CO^, H^O) 



