Febeuaby 3, 1911] 



SCIENCE 



165 



ripens its seed four weeks earlier than another 

 European kind. With these facts so plainly- 

 showing inherited acclimatization, we may readily 

 believe Kalm, who states that in North America 

 maize and some other plants have gradually been 

 cultivated further and further northward. 



The peach tree offers another good in- 

 stance of acclimatization.^® 



Mr. Crozier records testimony to the efifect that 

 peach trees in Michigan were injured no more at 

 a temperature of twenty degrees below zero than 

 they were in central Mississippi at a temperature 

 of zero. Peach buds are injured at a much higher 

 temperature at the south than at the north. 

 Mr. P. H. Mell, Jr., director of the Alabama 

 Polytechnic Institute at Auburn, writes me that 

 buds are often killed even at a temperature of 

 34 to 38 degrees above zero. This observation 

 undoubtedly refers to the parJally expanded 

 buds, yet it is well known that at the north a 

 considerable frost is required to kill the swelling 

 buds. It is possible that all these instances of 

 the peach should fall under the division of adap- 

 tation through modification of individual consti- 

 tution; but as I can not be certain, if indeed it 

 is probable, that all these cases represent bud 

 offspring, I place the statement here. If trees of 

 the same variety show this difference in diiferent 

 latitudes, as they undoubtedly often do, then we 

 have indisputable evidence of the acclimatizing 

 of the individual. 



Bailey's quotation from Cooper as to 

 watermelons also has a bearing on this 

 matter.^" 



A striking instance of plants being naturalized 

 happened by Colonel Matlack sending some water- 

 melon seed from Georgia, which, he informed me 

 [Cooper] by letter, were of superior quality. 

 Knowing that seed from vegetables which had 

 grown in more southern climates required a 

 longer summer than what grew here, I gave them 

 the most favorable situation, and used glasses to 

 bring them forward, yet very few ripened to per- 

 fection; but finding them to be so excellent in 

 quality as described, I saved seed from those first 

 ripe; and by continuing that practise four or five 

 years, they became as early watermelons as I 

 ever had. 



^° Bailey, "The Survival of the Unlike," 325, 

 1896. 

 ™ Bailey, " The Survival of the Unlike," 154, 



Changes in the colors of some butterflies 

 can be obtained by varying the tempera- 

 ture during the pupal stage of develop- 

 ment. While we are not able to prove that 

 these changes are beneficial adaptations, it 

 is interesting to note that these changes 

 characterize the same butterflies in arctic 

 and tropic regions.^^ 



Warmth acting on pupse of V. Cardui (painted 

 l^dy), gave an extraordinarily pale form, like 

 those found in very difi'erent parts of the tropics. 

 Cold, on the other hand, gave specimens with a 

 very recognizable darkening of the whole insect, 

 such as is exhibited by a form found in Lapland. 



We have no clue" at all as to the influ- 

 ence a low temperature has upon the pro- 

 duction of wings in aphides. "As long as 

 the temperature is high and the moisture 

 sufficient, plant lice are wingless, but if the 

 temperature be lowered, wings begin to 

 grow. ' ' The problem is an interesting one 

 and should not be difficult to solve with 

 the aid of the theorem of Le Chatelier. 



Since light tends to destroy any sub- 

 stance which absorbs it, it seems at first 

 sight as though transparent, colorless 

 plants and animals would be the surviving 

 type in the intense light of the tropics. 

 Light does tend to bleach organic col- 

 ors; but the flaw in the reasoning is that 

 we are dealing with living organisms.^' It 

 is easier for a man or an animal to develop 

 a pigmented coating and thus eliminate 

 the chemical action of light on blood'* than 

 for it to acquire the habit of living without 

 red corpuscles. It is evidently better for a 

 plant to develop chlorophyll and a healthy 



" Vernon, " Variations in Plants and Animals,"' 

 237, 1903. 



^Loeb, "The Dynamics of Living Matter," 112, 

 1906. 



^Cf. Eimer, "Organic Evolution," 136, 1890. 



^ Cf. Woodruff, " Effects of Tropical Light on 

 White Men," 10, 85, 1905. 



