XIX.] WHAT IS ACCLIMATIZATION? 321 



mine whether a given phenomenon is acclimation or 

 acclimatization. If the phenomenon occurs in plants 

 which are in any manner or degree cultivated, it falls 

 under the head of acclimatization, as the word is 

 used in this discussion. The reader must also remem- 

 ber that plants become acclimatized in various ways 

 without beeoming hardier. Increase in hardiness is by 

 no means the only proof of acclimatization, although 

 common opinion seems to consider it so. 



The literature of the subject is in most cases value- 

 less, because the idea of overcoming climate is not 

 kept in mind. Nor is it safe to say that because a 

 given sub -tropical plant has been extended over wide 

 temperate areas, it has become acclimatized. The plant 

 may originally have had sufficient flexibility of consti- 

 tution to allow it to thus extend its range. Again, if 

 acclimatization occur it must necessarily be a very slow 

 process, and the science of plant observation in the 

 garden is not yet old enough to present many definite 

 facts. Add to these difficulties the fact that many 

 writers wholly deny the possibility of acclimatization, 

 and the subject is seen to be exceedingly perplexing. 



Those who wholly deny acclimatization are for the 

 most part unreasonable in their demand of what accli- 

 matization should be. They demand that plants be 

 adapted to an opposite extreme of climate before they 

 be called acclimatized. It is not to be expected that 

 the plant * can be so radically changed. A slight 

 change, as well as a great one, is acclimatization. 1 

 repeat the definition : 



Acclimatization. — The act or aid of man in inuring or habitu- 

 ating a species or variety to a climate at first injurious to it, 

 or the state or condition of being thus inured or habituated. 

 21 SUR. 



