230 THE CONTTtOL OF LIFE 



well as old ; a whole lagoon may be cleared out ; the 

 supplies obtained are far in excess of demand. What 

 a contrast this wastefulness is to the conservative 

 expedient of tumbling cartloads of bracken into a fresh- 

 vrater loch, with the result that the trout-supply in suc- 

 ceeding years is greatly increased. The bracken, worked 

 on by bacteria, affords food for Infusorians, which are 

 devoured by minute crustaceans, which form the food of 

 the trout, which are in turn reincarnated in man. Most 

 of us will prefer this way of eating bracken to that 

 counselled by some frugal minds who recommend 

 bracken-top asparagus and bracken-root fritters. The 

 indirect way of eating bracken is the more scientific. 

 To economists in the days of Malthus the danger of 

 human population outrunning the means of subsistence 

 was a dark cloud ; it would not have seemed so dark 

 if they had known what we know of Man's power of 

 multiplying loaves and fishes, e.g. by rearing more pro- 

 lific strains of cereals or by artificial stimulation of the 

 resources of the sea. It is not indeed to be supposed 

 that there is not much wastefulness in modern methods 

 of exploitation, — in trawling, for instance,— but the 

 point is that we know more or less clearly when we are 

 -wasteful, that we can stop it when we choose, and that we 

 can increase our food-supply enormously whenever we 

 please to put more brains, i.e. more science, into the 

 problem. 



It is easy to exhaust mussel-beds unless they are 

 used in a series, giving each a long rest in turn ; it is 

 easy to exhaust a field unless there be rotation of crops ; 



