250 Of the Checks to Population Bk. i. 



" Thrace, and Egypt ; yet the number of people 

 " did not increase in Italy ; and writers complain 

 " of the continual decay of industry and agricul- 

 " ture."* It seems but little probable that the 

 peace under Trajan and the Antonines should 

 have given so sudden a turn to the habits of the 

 people as essentially to alter this state of things. 



On the condition of slavery it may be observed 

 that there cannot be a stronger proof of its unfa- 

 vourableness to the propagation of the species in 

 the countries where it prevails, than the necessity 

 of this continual influx. This necessity forms at 

 once a complete refutation of the observation of 

 Wallace, that the ancient slaves were more ser- 

 viceable in raising up people than the inferior 

 ranks of men in modern times.f Though it is 

 undoubtedly true, as he observes, that all our 

 labourers do not marry, and that many of their 

 children die, or become sickly and useless through 

 the poverty and negligence of their parents;^: yet, 

 notwithstanding these obstacles to increase, there 

 is perhaps scarcely an instance to be produced 

 where the lower classes of society in any country, 

 if free, do not raise up people fully equal to the 

 demand for their labour. 



To account for the checks to population which 

 are peculiar to a state of slavery, and which render 

 a constant recruit of numbers necessary, we must 

 adopt the comparison of slaves to cattle which 



* Essay xi. p. 433. 



t Dissert, on the Numbers of Mankind* p. 91. 



\ Id. p. 88. 



