THE ENERGY OF THE LIVING PROTOPLASM. 183 



tion products by it, while they remain colourless during their stay 

 in normal cells. (I) 



How weak the oxidising power of the cells appears to be here 

 and then how energetic when sugar comes under action ! We 

 search the entire domain of chemistry in vain for a single case of 

 the occurrence of complete combustion when an organic compound 

 in aqueous solution absorbs oxygen from the air; (2) even the well 

 known energetic absorption of oxygen by alkaline solution of 

 pyrogallol does not lead to a complete combustion. Only the 

 action of free permanganic acid can exhibit similar results. 



However, there exist cases where partial oxidations by 

 molecular oxygen can easily take place. We will mention the 

 transformation of aldehydes into acids, of hydrazo-benzene to 

 azobenzene, of indigo white into indigo blue. Also the be- 

 haviour of anthraquinone, oxindol, and amidophenols to common 

 oxygen may be cited. The total change here taking place 

 consists either in the entrance of one oxygen atom into the 

 molecule or in the withdrawal of two hydrogen atoms. Other 

 compounds again acquire the property of absorbing free oxygen 

 through the presence of an alkali, as pyrogallol, pyrogalloquinone, 

 chrysarobin, furoin. (3) Benzene acquires it by the presence of 

 aluminium chloride. In all these cases there exists evidently a 

 high degree of lability in certain hydrogen atoms leading to the 

 absorption of oxygen. This lability is due to their specific posi- 

 tion in the molecules. (+) We observe under ordinary circum- 

 stances, however, no labile hydrogen atoms in the fatty acids 

 proper, but nevertheless the latter are easily burned up in the 

 cells. We must then logically conclude that contact with the 

 living protoplasm suffices to impart a state of lability to the atoms 

 in the molecules of the fatty acids, recalling the action of 



(1) Ber. Sachs. Akad. d. Wiss., 1889, p. 493. These observations likewise proved 

 the absence of H2O2 in plant-cells. 



(2) It is obvious that the energetic autoxidation of zinc ethyl, dimethyl arsine, 

 monobrom-acetylene and of the sodium compounds of ketones and aldehydes, which 

 burst into flame in contact with air cannot serve for comparison. 



(3) A preliminary " activifying " of oxygen takes place here just as little as in 

 the living protoplasm. 



(4) Lability of hydrogen linked to carbon miy be of two kinds: one which 

 determines its easy exchange by certain metals, as in acetylene, the other which 

 causes its increased affinity for oxygen, as in aldehydes. 



