166 SCIENCE PROGRESS 
an extra amount of oxygen for their complete removal during 
the subsequent oxygen period. To take a concrete instance, one 
suggested by Winterstein, the decomposition of a carbohydrate 
molecule may take place in the following two stages: 
C.H,,0, = 2C,0,0--+ 260; 
2C,;H,O + 60, = 6H;O + 4CO.. 
The change represented by the first equation results in the 
formation of a third of the total CO, output, though no oxygen 
is drawn upon whatever ; whilst according to the second equation 
the complete oxidation of the alcohol— a “ fatigue product” pro- 
duced by the first decomposition—requires 6 volumes of oxygen 
for every 4 volumes of CO, formed, or yields a respiratory 
quotient of *67. 
Arguing against the somewhat inconclusive evidence of the 
existence of intramolecular oxygen, Winterstein adopts the 
views long since suggested by Detmer, that the primary source 
of the energy developed in living organisms is not of an oxida- 
tive nature, but consists rather in the disintegration of highly 
complex labile compounds, the decomposition products of which 
subsequently undergo oxidation. That under certain conditions 
vital energy can be developed in the absence of contemporary 
oxidation is undoubted, for we know that certain bacteria, as 
B. anthracis and B. tetam, live and flourish best under completely 
anzrobic conditions. It seems very probable, also, that some of 
the energy liberated in zrobic organisms may be of similar 
origin, but we cannot for a moment imagine that all the energy 
is developed in exactly the same way. Much, perhaps most of 
it, is in all probability formed as the result of contemporary 
oxidation. If this is the case, then a supply of immediately 
available intramolecular oxygen is essential, and arguing from 
the weight of evidence, which is admittedly not quite con- 
clusive, we should provisionally adopt the doctrine of its 
existence. 
We must now pass on to a discussion of what is actually 
known as to the processes of oxidation in the tissues. Mention 
has frequently been made in the above pages of the collection of 
fatigue products in the tissues, which subsequently undergo 
further oxidation; but are such products matters of fact, or mere 
figments of fancy? Some of the most interesting evidence 
