THE EVOLUTION OF LIVING BEINGS. II7 



as criteria the protective measures against wet feet, 

 a cow is an infinitely higher animal than man. 



The much met with criterium : higher differentiation 

 indicates a higher, less differentiation a lower degree of 

 development, is no good either; by this measure am- 

 phibia, generally considered to be „higher" than fis- 

 hes, would have to be placed lower than these on the 

 progressive scale, because they lack a good deal of dif- 

 ferent ation in the skeleton, in the sense-organs of 

 the skin, in the covering of it, in the brains, with the 

 exception of the Pallium, and in the ovarium, which the 

 Teleosts possess. 



Comparison of the characters consequently gives 

 no criterium for progression, so that it is very possible 

 that progression has as litte real existence in nature 

 as genera have, but that progression is an abstraction 

 of the human mind just as the genus is. 



But we are not yet justified to draw this con- 



slusion ; there is something, called the geological re- 

 cord, the record — even if it be very incomplete — of 

 the development in time which according to the 

 opinion of many, proves that progression does exist ! 



It proves nothing of the kind ; it proves, at the most, 

 that the succession was: Coelenterata, Molluscs, Fis- 

 hes, Reptils, Birds, Mammals, to mention only the 

 groups referred to above, but this of course does not 

 prove, that the forms which made their appearance 

 the latest, are the highest ones (did not much „higher" 

 reptils appear much earlier than the present, „lower" 

 ones?). One might, with equal justice, claim mental 

 superiority for the child which is last born ! 



ix 



