some and second in thf- chroiiatin of the nucleus. 



The experinents here reported offer strong support to 

 the theory that the nucleus is the organ of synthesis. 

 Ahen a cell is depri /cd of food, the processes of synthesis 

 must, to a great extent, come to a ston, altho synthesis 

 of intermediary products of metabolism Is still possible, 

 it is probably not a coincidence that a cell deprived of 

 its nucleus lives almost as long as a cell deprived of food. 



An opportunity to put the synthesis theory to a direct 

 test was afforded by nutritional experiments. W>->en amebas 

 are kept v/fthout food, they v/ill die in from one to two 

 weeks, but if glucose is present in solution their life is 

 somewhat prolonged. It appears that the glucose is used as 

 a food. When urea was added the organisms lived even longer, 

 and in some cases divided. Urea alone, wit'-iout glucose, had 

 no such effect, a fact v/hich is interpret ted as meaning that 

 the nitrogen compund is combined by the cell with the carbon 

 compound. When nitrogen v/as already com.bined with unoxidised 

 carbon, as in the amino-acids, the addition of glucose was 

 unnecessary. 



When these experiments were repeated upon the e-ucleated 

 cell, it was found that glucose was some "hat beneficial, and 

 was apparently used as a food. But the further addition of 

 urea was not only of no benefit, but actually hastened the 

 death of the protoplasm. Apnarently non-nuclear protoplasm 



(65) 



