16 TOILERS IN THE SEA. 



Examinations of the deep-sea bottom, made at 

 intervals during the past eighty years, have revealed 

 the fact that the ocean bottom at great depths, say 

 from 500 to 3,000 fathoms, consists largely of a 

 tenacious mud, in which a great number of animals 

 exist, obtain nourishment, and increase their species. 

 Various hypotheses have been offered as to the 

 manner in which such conditions have been made 

 possible. How nourishment could be furnished at 

 such extreme depths has been the initial question. 

 Dr. Wallich suggests that the Rhizopods of the deep 

 sea must have the faculty of separating the elemen- 

 tary constituents of their bodies from the surrounding 

 medium. 1 It has been contended that only organ- 

 isms containing chlorophyll "have the power of 

 producing albuminoid compounds from carbonic 

 acid, water, ammonia, and nitric acid." Dr. Car- 

 penter was inclined to accept the view propounded 

 by Thomson, that "the Protozoa of the deep sea 

 are nourished by protoplasm which is diffused 

 through the whole mass of sea-water, renewed con- 

 stantly by the plants and animals living at its 

 surface, and penetrating by diffusion to its greatest 

 depths." 2 Gwyn Jeffreys suggested that the de- 

 composed organic mass was derived from animals 



1 " North Atlantic Sea Bed " (1862) p. 130. 



2 Nature, March 31, 1870. 



