COUNCIL - MARCH 1920 - APPENDIX — 72 — 



The economic species is the final link in a chain of metabolism from the ulti- 

 mate foodstuffs and energy of sunlight and each link has to be considered under 

 two heads : — 



1) the relation of the organism to sea-water, and 



2) the relation of the organism to other organisms. 



1) The sea-water contains the ultimate foodstuffs (ammonia, nitrate, carbon 

 dioxide, oxygen, phosphates, inorganic ions such as Na', R', Ca", Mg", Cl', S04" 

 etc.), in respect to which we require to know how they are taken up under optimum 

 conditions. The problem, however, is not limited to this, for inorganic ions play 

 an essential role in vital processes apart from their necessity in the chemical compo- 

 sition of tissues. Indeed it would appear that many organisms can only maintain 

 their normal conditions when the balance between the various ions lies between 

 narrow limits. The growth of such organisms depends on a factor which has seeming- 

 ly nothing whatever to do with the internal metabolism of the "cells." 



The main problem hence divides further into, 



A) the relation of plant life to the ultimate food stuffs, 



B) the relation of every link in the chain to the ions of sea-water. 



Under the latter head falls the consideration of the optimum conditions for 

 fertilisation, growth and distribution. 



The consideration of the ultimate food stuffs is important. Are they taken 

 up by plants alone ? The role of bacteria will require careful consideration. The 

 possibilities suggested by the work of Putter and others as to sea-water containing 

 soluble food substances (animo-acids, etc.) demands the most careful investigation. 



2) Every organism is a link on some chain leading to economic species. 

 Fishery naturalists are now studying the main organisms, their metabolism, growth, 

 reproduction and distribution. 



The following heads may be suggested in the research : ■ — 



(I) Pure Physical chemistry of sea-water. 

 How do such conditions as temperature, depth, nature of the bottom, currents, 

 lack or abundance of plant or animal life etc. change the constituents of sea-water ? 

 Why and how do they act? A study of the various factors, the adjustment of which 

 produced the physico-chemical equilibrium in the sea, is wanted in the hope of get- 

 ting an adequate picture of this equilibrium. 



(II) Applied physical chemistry of sea-water. 

 Much research requires the use of sea-water containing other chemicals 

 and it is necessary to know exactly how these solutions differ from sea-water if the 

 conclusions from this research are to be of value. 



