SYMBIOSIS 41 



That under conditions of depredation and mutual plunder 

 the plant cannot function as symbiotically and therefore as 

 adequately as under conditions of mutual co-operation is as 

 self-evident as it is also conspicuously apparent in nature. 

 The energies spent by a plant in the production of poisons for 

 self-defence like the capital spent by modern nations for 

 armaments is at the expense of productiveness in other direc- 

 tions. With plant species destroyed in numbers by animal 

 depredation and with many plants turning poisonous for pro- 

 tective purposes, animals in many instances have had to turn 

 upon other animals until a fair equilibrium between plant and 

 animal is again restored such is " der Fluch der bosen That." 

 In the ocean, for instance, the quantity of plankton is held to 

 depend upon the proportion that the destruction of algse by 

 physical and animal agency bears to their production, and if, 

 as Prof. Keeble assures us, most marine animals are always 

 ravenous, we may conclude that it is at bottom the lack of 

 biological symbiosis which is a primary cause of unnatural and 

 morbid craving which comes under the head of what I have 

 termed a parasitic diathesis. Retrograde symbiosis leads to 

 insufficiency of food-supply, with its subsequent temptations 

 and necessities, and conduit a la mart rather than to genuine 

 survival. 



Just as a leaf detached from the tree is at once cut off from 

 a supply of water and salts, and is deprived of the means of 

 getting rid of organic substances which it produces and must 

 consequently suffer considerable alteration of concentration 

 so an organism detaching itself from genuine biological 

 symbiosis is gradually deprived of the possibilities even of 

 fruitful interchanges with the biological community, and is 

 certain to undergo such changes in its constitution as in turn to 

 divorce its kind ever more and more from symbiogenetic 

 progress, from the perennial plasticity of the truly symbiotic 

 organisms. 



I shall have to revert in a subsequent chapter to the matter 



