The Making of Species 



much as by their inherited tendencies. In this 

 respect they differ very considerably from the 

 higher animals. The peacock, for example, 

 presents the same outward appearance 1 whether 

 bred and reared in Asia or Europe, in a hot or 

 cold, a damp or a dry climate, The same plant, 

 on the other hand, differs greatly in outward 

 appearance according as it is grown in a dry or a 

 damp soil, a hot or a cold country. In his recent 

 book The Heredity of Acquired Characters in 

 Plants, the Rev. G. Henslow cites several 

 examples of the celerity with which plants react to 

 their environment. On page 32 he writes : " The 

 following is an experiment I made with the 

 common rest-harrow (Ononis spinosa, Z.) growing 

 wild in a very dry situation by a roadside. I 

 collected some seeds, and also took cuttings. 

 These I planted in a garden border, keeping this 

 well moist with a hand-light over it, and a saucer 

 of water, so that the air should be thoroughly 

 moist as well. Its natural conditions were thus 

 completely reversed. They all grew vigorously. 

 The new branches of the first year's growth bore 

 spines, proving their hereditary character, but 

 instead of their being long and stout, they were 

 not an inch long, and like needles. This proved 

 the spines to be a hereditary feature. In the second 

 year there were none at all ; moreover, the plants 



1 The white, pied, and " Japan " individuals are not more different 

 from the type than some variations occurring in wild birds. 



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