VII.] TRANSMISSION OF ACQUIRED CHARACTERS, 419 



it cannot be doubted that the character has become fixed by 

 hereditj^ Where, however, is the proof that this hereditary- 

 character has been produced by the direct influence of climate ? 

 What right have we to look upon the hereditary appearance 

 of the character as an after-effect of the direct influence exerted 

 by changes of temperature upon previous generations ? Such 

 an opinion derives but little support from the previously de- 

 scribed experiments upon after-effect, which showed that these 

 phenomena were never hereditary. 



It appears to me that there are certain points in this change 

 of leaf and its accompanying phenomena, which distinctly 

 indicate that natural selection has been at work. Can Detmer 

 imagine that the brown scales which form the characteristic 

 protective covering of winter buds have been produced by the 

 direct action of the cold ? If, however, the peculiar structure 

 of these buds is to be referred to the specific constitution of 

 the individual rather than to the direct effects of climate, would 

 it be so very improbable for their physiological peculiarity of 

 lying dormant for several months to have been developed 

 simultaneously with the structure, by the operation of natural 

 selection ? And if this explanation be correct, we can at once 

 see why the character has become hereditary, for natural 

 selection works upon variations of the germ-plasm, and these 

 are transferred from one generation to another with the germ- 

 plasm itself. 



But Detmer attempts to establish the converse conclusion, 

 and he argues that the hereditary change of leaf has been 

 abandoned under the long-continued effect of changed climatic 

 conditions ; but this opinion is based upon the single instance 

 of the alteration in the habit of the European cherry in Ceylon. 

 If it were proved that our cherry, grown from seed in Ceylon 

 and propagated by seed for several generations, became ever- 

 green gradually and not suddenly in the first generation : if, 

 under such circumstances, it came to retain its leaves in the 

 autumn and ceased to produce the dormant winter buds : — 

 then indeed the transmission of acquired characters could 

 hardly be doubted. I am not a botanist, but I believe I am 

 right in supposing that the wild cherry reproduces itself by 

 seeds, while the edible domesticated cherry is propagated by 

 grafting. Grafts are, however, parts of the soma of a previously 



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