934 LIFE : OUTLINES OF GENERAL BIOLOGY 



already seen, there is building-up and breaking-down, repair and 

 waste, assimilation and disassimilation, income and expenditure, 

 anabolism and katabolism. This is a common-sense fact — the comple- 

 mentary balance of feeding and working, of stoking the engine and 

 burning the fuel. It is also a fundamental fact of biochemistry, that 

 metabolism has these two aspects — constructive or anabolic, and 

 disruptive or katabolic. Every living creature must keep a balance 



between these antithetic processes, but the ratio of the two, — , 



varies greatly from type to type, as well as in their own lives, 

 the condition being that for the general maintenance of life the 

 numerator must always be kept greater than the denominator. 

 The continual * 'winding up of the clock" is characteristic of life, 

 but in many organisms the clock runs down very quickly, in 

 others very slowly. Thus there is the contrast between relatively 

 active and relatively sluggish tjrpes. But a very active animal, 

 fike a tjrpical bird, must have much more anabolism for its 

 weight than a sluggish reptile, for it has to balance its intense 

 katabolism; so the contrast should always be stated as a ratio. 



Measured for a short time, the ratio ~ for a flying bird will be 



less than that for a sluggish reptile of the same weight, although 

 the numerator for the bird will be greater for a week than it is for 

 the reptile. 



The fundamental dichotomy among organisms, leading on to 

 secondary and tertiary dichotomies, is just this divergence between 

 the relatively more active or katabolic and the relatively more 

 passive or anabolic. It may be discerned between plants and animals, 

 which tjrpically differ from one another as munition works from 

 active batteries. In virtue of their photo-synthesis, elsewhere dis- 

 cussed, green plants have extraordinarily preponderant anabolism; 

 they make and store abundance of reserves of energy which animals 

 may eventually utilise in energetic, sometimes almost explosive 

 activity. This contrast between plants and animals has exceptions, 

 of course, but they prove the rule by their rarity, such as the sema- 

 phoring Telegraph Plant {Desmodium gyrans) of the steamy Ganges 

 basin and the female cochineal insect heavily laden with her store 

 of carmine. Some flowers, like the "Calla Lily," have a temperature, 

 and a massive coral has far more lime than living matter, but 

 neither of these is in any way typical. 



All through what we can discern of the past evolution of animals 

 we see the same forking of the ways. It stands out in the contrast 

 between a sluggish Sporozoon, like the Monocystis parasite of all the 

 common earthworms, and an intensely active Infusorian like the 

 Noctiluca that sets the waves on fire in the short summer darkness ; 

 between the sedentary corals in their thick- walled castles of indolence 



