302 EVOLUTION, OLD AND NEW. 



modifications. In like manner, our modern evolutionists 

 should allow that animals are modified not because they 

 subsequently survive, but because they have done this 

 or that which has led to their modification, and hence 

 to their surviving. 



Having established that animals and plants are 

 capable of being materially changed in the course of a 

 few generations, Lamarck proceeds to show that their 

 modification is due to changed distribution of the use 

 and disuse of their organs at any given time. 



" The disuse of an organ" he writes, "if U heeomes 

 consta/nt in consequence of new habits, giraduaily reduces 

 the organ, and leads fmally to its disappearanee." * 



" Thus whales have lost their teeth, though teeth 

 are still found in the embryo. So, again, M. Geoffrey 

 has discovered ^n birds the groove where teeth were 

 formerly placed. The ant-eater, which belongs to a 

 genus that has long relinquished the habit of masti- 

 cating its food, is as toothless as the whale." t 



Then are adduced further examples of rudimentary 

 organs, which will be given in another place, and need 

 not be repeated here. Speaking of the fact, however, 

 that serpents have no legs, though they are higher in 

 the scale of life than the batrachians, Lamarck attri- 

 butes this "to the continued habit of trying to squeeze 

 through very narrow places, where four feet would .be 

 in the way, and would be very little good to them, 

 inasmuch as more than four would be wa-nted in order 

 to turn bodies that were already so much elongated." X 



If it be asked why, on Lamarck's theory', if serpents 



• ' Phil, Zool,,' torn. i. p 240. t Page 241. J Page 245. 



