1909.] NATURAL SCIENCES OF PHILADELPHIA. 109 



120 days and capable of maximum yields (75 bushels per acre), 

 to be grown in Michigan, Wisconsin, Maine and Mississippi. In 

 Maine it failed to ripen, but at all other points it ripened in about 

 100 days, producing small, inferior ears. That it should hurry 

 through its period of growth at the north was not surprising, but that 

 it should do so in the south is unaccountable. 12 The season of maize 

 varies from six months in the elevated plains of Santa Fe in South 

 America to four months in the middle United States and two and one- 

 half months in the rainy lake district northwest of Lake Superior. 13 

 Peach trees from central Georgia blossom ten to twelve days later in 

 Virginia and Maryland than do those of the same variety from New 

 Jersey or New York. As peach trees are propagated by buds we may 

 regard the Georgia and New Jersey trees, being of the same variety, as 

 parts of the same individual. The foregoing citations indicate that 

 acclimatization does occur, and that in the case of the experimental 

 twigs the differences in the time of the bud development illustrates 

 that acclimatization has taken place to the extent of a variation in 

 habit as to their seasonal development, emphasized in the acclimatiza- 

 tion of the cotton, corn and peach previously described. 



The response of the buds in the chemical solutions was an immediate 

 one, and at a season of the year when all of the twigs from widely sepa- 

 rated stations (north and south) were in a dormant condition. The 

 advantage of these experiments in demonstrating the above conclusions 

 is marked over the growth of such trees in the forest, or in the orchard, 

 for the reason that as to temperature all of the twigs were exposed 

 equally to the same amount, and those placed in the pure water were 

 under practically the same conditions, while the chemical solutions 

 provided enough of different conditions under experimental control 

 which would produce alterations in the time and method of response, 

 if such could be produced by experimental means. The results have 

 already been summarized. 



Bibliography. 



Bailey, L. H.: Survival of the Unlike. 1896 : 320-333. Acclimatization: 

 Does it Occur? 



Bose, Jagadis Chunder: Plant Response as a Means of Phvsiological Investi- 

 gation, 1906: 361, 382-383, 386-387. 



Cannon, W. A.: Acclimatization of Plants. The Plant World. XI: 113-114, 

 May, 1908. 



■Carlier, M. A.: Memoire sur l'Acclimatement des Races en Amerique. Paris, 

 1867, pp. 55. 



12 Davenport, E.: Principles of Breeding, 1907, p. 222. 



13 Bailey, L. H.: Survival of the Unlike, 1896, p. 329. 



