506 STUDIES IN GENERAL PHYSIOLOGY 
energetically. The majority of investigators believe that 
oxygen is activated in the tissues, and that in this process 
certain substances act catalytically which, after Traube, we 
will call “oxygen carriers.” It has been possible to extract 
these oxygen carriers from the cells and to show that in this 
condition the oxygen carriers are still able to bring about 
those oxidations which are characteristic of living matter. 
The most valuable discovery in this direction was undoubt- 
edly made by Spitzer.’ Spitzer has shown that those sub- 
stances in extracts of tissues, which favor the transfer of 
oxygen (oxidation ferments) belong to the group of nucleo- 
proteids. The nucleoproteids are typical substances of the 
nucleus. All these nucleoproteids contain iron. Now, we 
know that iron salts are especially adapted to accelerate 
oxidation. There is no reason to doubt that what is true 
for the aqueous extracts of the cells holds also for the 
nucleoproteids of living cells. Macallum has proved the 
existence of iron in the chromatin substance of the cell 
nuclei. The work of Spitzer, therefore, renders it probable 
that the nucleus is the organ of oxidation in living matter. 
We will now see whether the behavior of cell fragments 
without the nucleus corresponds to this assumption. Verworn 
describes the changes which occur in the pseudopodia in 
these cases as follows: In the pseudopodia of an enucleated 
piece of Orbitolites droplets are formed which, in part, flow 
together into larger drops. The connection between the 
individual drops disappears. ‘Finally, after about five to 
seven hours the central portion forms a round lump without 
pseudopodia, around which are scattered a number of larger 
and smaller globules, drops, and spindles of protoplasm.” 
Verworn in adopting and misunderstanding the view of 
Berthold has developed a theory of amceboid movements 
1 Pfliigers Archiv, Vol. LXVIT (1897), p. 615. 
2 VERWORN, Pfliigers Archiv, Vol. LI (1892). 
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