392 THE EVOLUTION OF LIFE. 



positions. Yon Baer writes — "A fish, swimming towards 

 the shore, desires to take a walk, but finds his fins useless. 

 They diminish in breadth for want of use, and at the same 

 time elongate. This goes on with children and grandchil- 

 dren for a few millions of years, and at last who can be as- 

 tonished that the fins become feet ? It is still more natural 

 that the fish in the meadow, finding no water, should gape 

 after air, thereby, in a like period of time developing 

 lungs ; the only difficulty being that in the meanwhile, 

 a few generations must manage without breathing at 

 all." Though, as thus presented, the belief in a 



transition looks laughable ; and though such derivation of 

 terrestrial vertebrates by direct modification of the piscine 

 type, is untenable ; yet we must not therefore conclude that 

 no migrations of the kind alleged can have taken place. 

 The adage that " truth is stranger than fiction," applies quite 

 as much to Nature in general as to human life. Besides the 

 fact that there are certain fish which actually do " take a 

 walk " without any very obvious reason ; and besides the 

 fact that sundry fish ramble about on land when impelled 

 to do so by the drying- up of the waters inhabited by them ; 

 there is the still more astounding fact, that one kind of fish 

 climbs trees. Few things seem more obviously impossible, 

 than that a water-breathing creature without efficient limbs? 

 should ascend eight or ten feet up the trunk of a palm ; and 

 yet the Anabas scandens does as much. To previous testi- 

 monies on this point, Capt. Mitchell has recently added 

 others. Such remarkable cases of temporary changes of 

 media, will prepare us for conceiving how, under special con- 

 ditions, permanent changes of media may have taken place ; 

 and for considering how the doctrine of evolution is eluci- 

 dated by them. 



Both marine organisms and fresh-water organisms, are 

 many of them left from time to time partially or completely 

 without water ; and the creatures which show the power to 

 ehauge their media temporarily or permanently, are in very 



