43 
Hence the view of Traube that nascent hydrogen atoms can reduce 
molecular oxygen to hydrogen peroxid can also be extended to /abil 
hydrogen atoms. 
The transformation of molecular oxygen into hydrogen peroxid is 
considered as an activifying of oxygen. In analogy with the forma- 
tion of hydrogen peroxid the peroxids of organic complexes also may 
be formed in certain processes of autoxidation, as Engler’ has recently 
shown for pinen, amylen, hexylen, styrol, cyclopentadién, and dial- 
lylether. Benzaldehyde yields by autoxidation, according to Baeyer,’ 
primarily benzoylated hydrogen peroxid, C,H,—CO—O—O—H, which 
easily transfers 1 atom of oxygen upon another molecule of benzalde- 
hyde, or upon some other easily oxidizable material, and thereby 
becomes benzoic acid. This would, however, not yet justify an 
attempt to extend the analogy also upon the oxidations caused by the 
living protoplasm, since it would involve a continuous oxidation of the 
protoplasm itself and lead to an early death of the cells before recon- 
struction of the injured parts would become possible. Nevertheless 
the proteids composing the living matter betray an aldehyde nature 
by the toxicological behavior of the living matter.’ 
The oxidations in the living protoplasm have often been ascribed to 
an activified oxygen, and doubtless many chemists would feel inclined 
to assume the formation of hydrogen peroxid in order to account for 
oxidations of which common oxygen seems incapable. But it must 
be considered that the great lability of the proteids of the living proto- 
plasm—in other words, the accumulation of kinetic chemical energy in 
them—is herea more important factor than the natural tendency of 
common oxygen or hydrogen peroxid to cause oxidation. © It is further 
a fact that hydrogen peroxid can not be utilized by the living proto- 
plasm as an oxidizer, since the active atomic groups in the proteids of 
the living matter would be oxidized by it instead of the thermogens 
stored up in the cells for combustion, and injury or death would result; 
indeed the highly poisonous character of hydrogen peroxid is well 
known.* Therefore, since the oxidation in the respiration process 
would take a detrimental turn if hydrogen peroxid accumulated as a 
by-product, the role of the catalase may possibly be explained. It 
would destroy every trace of this poisonous substance as quickly as it 
were formed and would thus afford an important protection. The 
' Berichte der Deutschen Chemischen Gesellschaft, vol. 33, p. 1103. 
?Tbid., p. 1582. 
3 These points are fully discussed in chapter 12 of the treatise of the writer, Die 
chemische Energie der lebenden Zellen, Munich, 1899, E. Wolff, publisher. 
‘In a dilution of 1: 200 hydrogen peroxid kills cholera bacilli in three minutes; of 
1: 15,000 it impedes development of typhoid bacilli; of 1:10,000 it kills infusoria in 
from fifteen to thirty-six minutes; and in one of 1:1,000 algze are killed in a short 
time. Intravenous injections kill mammals by stopping respiration. 
