of oxidation cease in the protoplasm." In support of this 

 view, Osterhout (lPx7) has recently published some inter- 

 esting observations upon the cells of the leaf of the 

 Indian Pipe. He finds that these cells become dark when 

 they are injured, owing to the oxidation of a pigment 

 which they contain; but that the darkening, and hence the 

 oxidation, occurs most readily in the nucleus. Prom this 

 he concludes that oxidation is most rapid in the nucleus of 

 the uninjured cell. These experiments will be discussed 

 later. 



That it is the protoplasm rather than the nucleus 

 which is concerned in respiration is indicated by tlie 

 experiments of Demoor (1895). Under conditions which 

 are known to depress oxidations, such as cold, and lack 

 of oxygen, or the presence of anesthetics, lemoor brot 

 the protoplasm of spirogyra cells into a condition of 

 inactivity; but the activity of the nucleus continued as 

 shown by its repeated divisions. In like manner the nu- 

 cleus of a frog's leucocyte continued its ameboid movements 

 after the cytoplasm had been rendered inactive by chloroform. " 



Child (1015) calls attention to the fact that anes- 

 thetics affect most ^uickly those regions which have the 

 most rapid respiration. 



(15) 



