PROTOPLASM AND CHROMATIN 91 



time, of converting nitrogen combinations. In the warm 

 oceanic waters the amount of Hme deposited is larger and the 

 variety of Hving forms is greater; but the number of Hving forms 

 which depend for food on the algae is less because the denitrify- 

 ing bacteria which flourish in warm tropical waters deprive the 

 algae of the nitrates so necessary for their development. Again, 

 where algal growth is scarce, the protozoic unicellular and 

 multicellular life (plankton) of the sea, which lives upon the 

 algae, is also less abundant. This affords an excellent illustra- 

 tion of the great law of the balance of the life environment through 

 the equilibrium of supply of energy^ one aspect of the interaction 

 of organisms with their life environment. The denitrifying 

 bacteria rob the waters of the energy needed for the lowest 

 forms of plants, and these in turn are not available for the 

 lowest forms of animal life. Thus in the colder waters of the 

 oceans, where the denitrifying bacteria do not exist, the num- 

 ber of living forms is far greater, although their variety is far 

 less.^ 



The so-called luminous bacteria also anticipate the plants 

 and animals in light production,'- which is believed to be con- 

 nected with the oxidation of a phosphorescing substance in 

 the presence of water and of free oxygen. 



Evolution of Protoplasm and Chromatin, the Two 

 Structural Components of the Living World 



It is still a matter of discussion'' whether any bacteria, even 

 at the present time, have reached the evolutionary stage of 

 the typical cell with its cell-wall, its contained protoplasm, and 

 its distinct nuclear form and inner substance known as chro- 

 matin. Some bacteriologists (Fischer) maintain that bacteria 



1 Pirsson, Louis V., and Schuchert, Charles, 1915, p. 104. 



2 Harvey, E. Newton, 191,5, pp. 230, 238. 'I. J. Kligler. 



