iOO LAWS OF MULTIPLICATION. 



drawn. Had the species to meet no repressing influence 

 save that negative one of relatively-diminished space or 

 relatively-diminished food-supply, the cause leading to its 

 increase might carry it up to the limit set by this, and there 

 ■leave it : its enlarged number might be permanent. But 

 the positive repressing influence that has been called into 

 existence, will prevent this. For the increase of enemies, 

 commencing, as it must, after the increase of the species, 

 and advancing in geometrical progression until it is itself 

 checked in like manner, will end in an excess of enemies. 

 Whereupon must result a mortality of the species greater 

 than its multiplication — a decrease which will continue until 

 its habitat is underpeopled, its unduly-numerous enemies 

 decimated by starvation, and the destroying agencies so 

 reduced to a minimum. Whence will follow another in- 

 crease. 



Thus, as before indicated {First Prin. § § 96, 133), there is 

 here, as wherever antagonistic forces are in action, an alter- 

 nate predominance of each, causing a rhythmical movement 

 — a rhythmical movement which constitutes a moving equili- 

 brium in those cases where the forces are not dissipated with 

 appreciable rapidity, or are re- supplied as fast as they are 

 dissipated. While, therefore, on the one hand, we see that 

 the continued existence of a species necessarily implies some 

 action by which the destructive and preservative forces are 

 self- adjusted ; we see, on the other hand, that such an action 

 is an inevitable consequence of the universal process of 

 equilibration. 



§ 322. Is this the sole equilibration that must exist ? 

 Clearly not. The temporary compensating adjustments of 

 multiplication to mortality in each species, are but intro- 

 ductory to the permanent compensating adjustments of mul- 

 tiplication to mortality among species in general. The above 

 reasoning would hold just as it now does, were all species 

 equally prolific and all equally short-lived. It yields no 



