186 TRANSACTIONS OF THE 



irrigation ; and finally, to the north of the Isthmus of Panama, in 

 Central America and Mexico, agricultural arts were highly devel- 

 oped, and here also they were dependent upon artificial irrigation. 

 From these six examples of high agricultural art, all the agricult- 

 ure of the world has been developed ; from these centers it has 

 spread. The petty agriculture of humid lands never went beyond 

 the utilization of little patches of ground in the forest glades until 

 it was borrowed in a higher state from arid lands. Everywhere with 

 the development of agriculture in the arid lands, the art of domes- 

 ticating animals was associated, and everywhere such animals were 

 raised for food, and to a large extent they were used as beasts of 

 burden. 



Now, it is to be noted that the animal industry eventually devel- 

 oped beyond the vegetal industry, and spread more widely, and 

 many tribal peoples became herdsmen and nomads before they came 

 to be agriculturists. -The art of domesticating animals was more 

 easily borrowed, especially in humid regions, than was the art of 

 agriculture. 



These industries enabled mankind to obtain a far more generous 

 subsistence and more thorough protection from unfriendly nature. 

 They thus caused a great increase in population. They also con- 

 stituted the first great agency for the accumulation of wealth, by 

 creating it in giving value to land, by creating it in flocks and 

 herds, and by storing it through the discovery of methods by which 

 the wants of the future could be met. By planting fields the wants 

 of to-morrow and all the days of the year to come are served; and 

 when the young of animals are reared, provision for future years is 

 made, and thereby men learn to accumulate. 



This change in the arts of life, and the increase of population 

 resulting therefrom, entirely changed the constitution of society. 

 In savage society, when mother-right prevails, a tribe is a group of 

 classes or clans living together in a village that is easily moved from 

 time to time. If a colony departs from a tribe, a segment of two 

 or more clans goes away and starts a new village, and the clans 

 again live as a village community upon the same plan as the parent 

 tribe. 



Now, let us suppose that a tribe separates by clans, so that each 

 goes off by itself; a curious condition arises therefrom : first, it 

 results in the divorce of all marriages, because husband and wife 

 are always of different clans ; and for the same reason the father is 



