THE LAWS OP VAKIABILITT. 63 



as the soil near the hovels of the natives would often be 

 in some degree manured, improved varieties would sooner 

 or later arise. Or a wild and unusually good variety of a 

 native plant might attract the attention of some wise old 

 savage ; and he would transplant it, or sow its seed. 

 That superior varieties of wild fruit-trees occasionally are 

 found is certain, as in the case of the American species of 

 hawthorns, plums, cherries, grapes, and hickories, speci- 

 fied by Professor Asa Gray. 



We now know that man was snfiBciently 

 civilized to cultivate the ground at ^n im- 

 mensely remote period ; so that wheat might have been 

 improved long ago up to that standard of excellence 

 which was possible under the then existing state of agri- 

 culture. One small class of facts supports this view of 

 the slow and gradual improvement of our cereals. In the 

 most ancient lake-habitations of Switzerland, when men 

 employed only flint-tools, the most extensively cultivated 

 wheat was a peculiar kind, with remarkably small ears 

 and grains. " While the grains of the modem forms are 

 in section from seven to eight millimetres in length, the 

 larger grains from the lake-habitations are six, seldom 

 seven, and the smaller ones only four. The ear is thus 

 much narrower, and the spikelets stand out more hori- 

 zontally, than in our present forms." So again with bar- 

 ley, the most ancient and most extensively cultivated 

 kind had small ears, and the grains were "smaller, 

 shorter, and nearer to each other, than in that now 

 grown ; without the husk they were two and one half 

 lines long, and scarcely one and one half broad, while 

 those now grown have a length of three lines, and almost 

 the same in breadth." These small-grained varieties of 

 wheat and barley are believed .by Heer to be the parent- 



