ANIMAL OXIDATIONS. 5 



numerous toxicological observations, the unstability of the active protein mole- 

 cule is due to the simultaneous presence of aldehyde and unstable ainino groups. 

 These occur separated from each other in the active proteins, and when they 

 combine the protoplasm dies, the molecule being changed into a stable condition, 

 i.e., into dead protein. It is also a fact that all substances which react with 

 aldehyde and unstable amino groups are poisonous to the living cells. 



LOEW has also shown, in conjunction with BOKORNY, that in many plants 

 a very unstable reserve-protein substance occurs, which to a certain extent occupies 

 an intermediate position between protein and organized living substance. 



The explanation as to the oxidation process differs entirely accord- 

 ing to the conception of the structure of the unstable protoplasmic 

 molecule. If the living protoplasmic protein is not, like protein in the 

 ordinary sense,, indifferent to neutral oxygen, we can admit of a cleav- 

 age of the oxygen molecule by this change. The protein would be itself 

 oxidized, while on the other hand a secondary oxidation of other dif- 

 ficultly oxidizable substances could be brought about by the oxygen 

 atoms set free. 



Another very widely diffused view exists in regard to the origin 

 of the activity of the oxygen, namely, that by the decomposition proc- 

 esses in the tissues, reducing substances are formed which split the 

 neutral oxygen molecule, uniting with one oxygen atom and setting 

 the other free. 



The formation of reducing substances during fermentation and 

 putrefaction is generally known. The butyric fermentation of dextrose 

 in which hydrogen is set free C6H 12 O6 = C4H 8 O2 + 2CO2 + 2H2 is an 

 example of this kind. Another example is the appearance of nitrates 

 in consequence of an oxidation of nitrogen in cases of putrefaction, 

 which process is ordinarily explained by the statement that reducing, 

 easily oxidizable bodies are formed which split oxygen molecules, liberat- 

 ing oxygen atoms which afterward oxidize the nitrogen. It is assumed 

 also that the cells of the animal tissues and organs have the power, like 

 these lower organisms which produce fermentation and putrefaction, 

 of causing splitting processes in which easily oxidizable substances, 

 perhaps also nascent hydrogen (HoppE-SEYLER 1 ), are produced. 



In accordance with what has been stated above on the oxidations in 

 the animal body, primarily a cleavage of the organic constituents of 

 the body takes place with the formation of readily oxidizable substances. 

 The oxidation of these latter produces an activation of the oxygen 

 and hence may also cause a secondary oxidation of dysoxidizable sub- 

 stances. The products formed by these splittings and oxidations may 

 perhaps in part be burned within the body without undergoing further 

 cleavage, but more probably they must first undergo a further cleavage 



1 Pfliiger's Archiv, 12. 



