TRANSITION FROM TRIBAL SOCIPiTY 293 



accumulation of wealth. As long as men li\('<l from hand 

 to mouth and consumed immediately ail lliat was pro- 

 duced, no enduring basis for formidable jiowcr existed. 

 But when men learned to store their food supply in flocks 

 and herds and to depend upon cultivated plants for their 

 subsistence, it was possible to lay aside an ever-increas- 

 ing fund of supplies, a sur])lns which could be drawn ui)on 

 in time of famine or other need. With the organization 

 of ]>atriarchal society, i)i'operty became an established 

 institution, and slavery became an important social sys- 

 tem. The captive of war was employed as a cowherd or 

 a shepherd. Since large flocks can be attended by rela- 

 tively few herdsmen, slavery did not reach its most ex- 

 tensive form of development until opportunity was af- 

 forded for the use of large numbers. The X)i'essure of 

 population upon the food supply developed a system of 

 cultivating the soil which, though arduous, was profitable, 

 provided a good supply of labor could be had. The slave 

 was forced into agricultural labor and cultivation of the 

 soil was then carried on upon a large scale. By the em- 

 ploATnent of gangs of slaves it was possible to produce 

 more wealth and thus increase the surplus. But if there 

 was no opi^ortunity to exchange the surplus products of 

 one locality for desired articles from other regions, there 

 w^as a definite limit to this surplus-producing cycle. 



It was only with the growth of barter and the increas- 

 ing possibility of exchanging surplus products that it be- 

 came profitable to augment both one's land and one's 

 slaves. A market for agricultural production must de- 

 velop and trade routes open up before slavery can be 

 liighly lucrative.^- But in addition to tlie existence of a 

 market, one other condition was essential to the spread of 



32 Seligman, op. cil., ]>]>. 154-ir)2. 



