Ch. ii. and the Mode of their Operation. 23 



rally operate with increased force. Vicious habits 

 with respect to the sex will be more general, the 

 exposing of children more frequent, and both the 

 probability and fatality of wars and epidemics will 

 be considerably greater; and these causes will 

 probably continue their operation till the popula- 

 tion is sunk below the level of the food; and then 

 the return to comparative plenty will again pro- 

 duce an increase, and, after a certain period, its 

 further progress will again be checked by the same 

 causes.* 



But without attempting to establish these pro- 

 gressive and retrograde movements In different 

 countries, which would evidently require more 

 minute histories than we possess, and which the 

 progress of civilization naturally tends to counter- 

 act, the following propositions are intended to be 

 proved : — 



1 . Population is necessarily limited by the 

 means of subsistence. 



2. Population invariably increases where the 

 means of subsistence increase, unless prevented 

 by some very powerful and obvious checks.f 



* Sir James Stuart very justly compares the generative faculty 

 to a spring loaded with a variable weight, (Polit. Econ. vol. i. 

 b. i. c. 4. p. 20.) which would of course produce exactly that kind 

 of oscillation which lias been mentioned. In the first book of his 

 Political Economy, he has explained many parts of the subject of 

 population very ably. 



f I have expressed myself in this cautious manner, because I 

 believe there are some instances, where population does not keep 

 up to the level of the means of subsistence. But these are extreme 

 cases ; and, generally speaking, it might be said, that, 



