THE ENERGY OF THE LIVING PROTOPLASM. I77 
time subsist on intramolecular respiration, as Pflüger has observ¬ 
ed in frogs, and Bunge in worms. (I) 
Although the comparison of respiration with direct com¬ 
bustion was close at hand, still there were many mysteries 
involved and many questions unsolved, in regard to the laws and 
to the causation of that energetic combustion going on at rela¬ 
tively low temperatures in a substance containing 75 per cent 
water and more, and yet remaining apparently intact, while 
effecting the union of the resorbed food with free oxygen. That 
the protoplasm remains alive while this fierce and destructive 
oxidation is carried on, appears the more notable as it is known 
how easily all kinds of living cells are killed by oxidising media 
in high dilutions, as by peroxide of hydrogen or by potassium 
permanganate. 
The views propounded by various authors exhibit conside¬ 
rable discrepancy. The oldest hypothesis, that of Schönbein , 
assuming the formation of ozone , had soon to be discarded. But 
nevertheless, the idea that the common oxygen had to be changed 
into an active form or modification before it could unite with the 
compounds in the cell, prevails also in the other theories. The 
supposed activifying process consisted in the splitting of the 
oxygen molecule into its two atoms with free affinities. (2) Hoppe- 
Seyler supposed that the living cells produce hydrogen, which in 
its nascent state could accomplish the “ activifying” process by 
combining with one of the atoms and setting the other free. But 
it was objected that hydrogen ought to make its appearance at the 
moment oxygen is being withdrawn. This was, however, never 
observed. Germinating seeds can exist one day, certain worms 
(Ascans) even 5-7 days, alive in absence of oxygen, but no trace 
of hydrogen is evolved by these organisms during that time. (3) 
Reinke holds that there exist in the living cells easily oxidisable 
organic matters, “ autoxidisers,” which are capable of suffering 
(1) With insufficiency of oxygen, animals will show albumen, glucose, and lactic 
acip in the urine ( Araki ), also an increase of oxalic acid ( Reale and Boeri). 
(2) This process would require a large amount of energy. Heat alone can 
accomplish it only at a temperature not lower than 1400° C. (Troost and Haute- 
fcuille). 
(3) M. Traube contends, moreover, that nascent hydrogen can activify oxygen ; 
it can merely produce peroxide of hydrogen. 
