376 TRANSMISSION 



climatic change, but so readily does it adjust itself, that new 

 varieties can be introduced successfully, provided they are given 

 considerable time to acclimate on a small scale before their pro- 

 duction under field conditions is attempted. 



Wheat has extended almost over the earth, except in extreme 

 latitudes. The varieties have become so well fixed in the various 

 regions that when brought from long distances they seldom thrive 

 at first. Some strains never succeed, but others acclimate per- 

 fectly in new localities. Varieties may be changed readily from 

 spring to winter sorts, and the hibernating habit become fixed, 

 as in other biennials. 



Imported animals are seldom fertile until acclimated. It is 

 said, however, that certain breeds of the dog never acclimate in 

 India sufficiently well to preserve their distinctive racial charac- 

 ters. On the other hand, species occasionally prosper better in 

 new localities than in old ones. Generally speaking, distance 

 makes less difference than altitude, temperature, sunlight, and 

 food supply. The evident principle involved is the influence, 

 favorable or otherwise, of certain elements of climate upon the 

 development of racial characters. 



Acclimatization to temperatures. It is a well-known fact that 

 if we bring together and put under the same conditions plants 

 or cuttings of the same species but grown in different latitudes 

 or altitudes, and therefore habitually exposed to widely different 

 temperatures, those from the more northern localities and the 

 higher altitudes will be the first to put out bud and leaf. 



De Candolle of Switzerland, and Bailey of New York, have 

 both conducted extensive experiments in this direction, and with 

 the same results. 1 



The former took, among others, cuttings of the poplar, the 

 tulip tree, and the catalpa, both from Montpellier and from 

 Geneva, and planted them at the latter place in glasses of water 

 with sand at the bottom. In every case those taken from 

 Geneva, the colder locality, leafed out first. The difference in 

 the case of the poplar was about twenty-three days, in the case 

 of the tulip tree about eighteen days, and in the case of the 

 catalpa twenty days. 



1 Bailey, Survival of the Unlike, pp. 296-301. 



