seem to give strong support to this theory: namely, the 

 experiments of Osterhout on the leaf of the Indian Pipe. 

 When the leaf of this plant is cut, the cells '."hich have 

 been injured soon become dark. Osterhout has shown that 

 this darkening is an oxidation, and since it occurs first 

 in the nucleus, argues that the nucleus is the center of 



A. 



oxidations. These experiments, however, admit of another 

 interpretation. It is reasonable to bel'elve that at the 

 center of the cell there is a strong reducing action, and 

 that very little oxygen is present. After the death of 

 the cell, however, oxygen, like other substances, may enter 

 freely, an J. in the dying cell it would be expected that ox- 

 idations would be very rapid in the neighborhood of the 

 nucleus, wliere the reducing action is greatest. In Oster- 

 houts experi^Tents, the cells ?/hich show the oxidative dark- 

 ening of the nucleus are those which have been injured by 

 cutting the leaf. Granted that the nucleus is the center 

 of oxidations in the cell v/hich is injured or dying, that 

 does not prove that it is the center of oxidations in the 

 normal living cell. 



Moreover, Kite and Chambers (1012) found, in cells 

 which were apparently uninjured, that reduction was most 

 rapid in the region of the nucleus. ITie dye janus green 

 becomes red (or— G-o-l-o-i'4-«-&e) when reduced. Kite and Chambers 

 observed that this reduction occurred first at the centro- 



(64) 



