SEA-FISHERIES LABORATORY. 325 



indirectly upon the plants, which would constitute, 

 therefore, the ultimate source of organised foodstuff in 

 the sea. In the long chain of dependent plants and 

 animals the plankton has been looked upon as providing 

 the first store of food, and, in fact, the phyto-plankton 

 may be regarded as the primary transformer of the 

 inorganic raw materials into the organic foodstuffs of the 

 animals. 



In '07, Putter* claimed that the principal source of 

 food was not to be found in the bodies of plants and 

 animals, but in organic compounds dissolved in the 

 water. The sea was to be regarded as a nutrient fluid in 

 which, for example, organic carbon compounds were 

 present in considerable quantity. This theory, if 

 accepted, must be of great importance in any treatment 

 of the metabolism of the ocean, and hence it must be 

 considered here. Rabent and Henze? have shown quite 

 recently that Putter's estimate of the organic carbon 

 compounds dissolved in sea-water was incorrect. Putter, 

 however, has lately ('09) § published another work in 

 which these corrections are accepted, without altering the 

 essential points in his theory. It is unnecessary to review 

 the whole work in detail here; but the subject may be 

 considered under three heads : — 



1. Do marine animals feed on solid food? 



2. Is this food sufficient for their needs? 



3. Is there more organic matter in solution in sea- 



water than is present in solid form (as plankton) ? 



There is no objection whatever, in the first place, to 

 be brought against the view that marine animals may 



* Zeitschrift /. allgem. Physiologic. Band VII, 2 and 3 Heft. 1907. 



f Wiss. Meeresunt. d. deut. Meere. Abteil. Kiel. Neue Folge, Band II, 

 1909. 



I Henze. P fingers Archiv. d. gesamte Physiologie, etc. Bd. 123, 1908. 

 § Die Ernahrung der Wassertiere. Jena, 1909. 



