SUMMAR Y OF ' PHJLOSOPHIE ZOOLOGIQUE: 275 



climate of Egypt itself do not appear to have changed. 

 If the conditions of life have not varied, why should 

 the species subjected to those conditions have done 

 so? Moreover, birds can move about freely, and if 

 one place does not suit them they can iind another 

 that does. All that these Egyptian mummies really 

 prove is, that there were animals in Egypt two or three 

 thousand years ago which are like the animals of 

 to-day ; but how short a space is two or three thousand 

 years, as compared with the time which Nature has had 

 at her disposal ! A time infinitely great qua man, is 

 still infinitely short qua, Nature.* 



" If, however, we turn to animals under confinement, 

 we find immediate proof that the most startling changes 

 are capable of being produced after some generations 

 of changed habits. In the sixth chapter we shall have 

 occasion to observe the power of changed conditions 

 [circonstances] to develop new desires in animals, and 

 to induce new courses of action; we shall see the 

 power which these new actions will have, after a certain 

 amount of repetition, to engender new habits and 

 tendencies ; and we shall also note the effects of use 

 and disuse in either fortifying and developing an organ, 

 or in diminishing it and causing it to disappear. With 

 plants under domestication, we shall find corresponding 

 phenomena. Species will thus appear to be unchange- 

 able for comparatively short periods only." t 



It is interesting to see that Mr. Darwin lays no less 

 stress on the study of animals and plants under domes- 

 tication than Buffon, Dr. Darwin, and Lamarck. 

 * ' Phil. Zool.,' torn. i. p. 88. t Page 90. 



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