PREFACE. XV 



Hipparion was the ancestor from which the horse of 

 the present day was evolved is an inconsequence ; 

 the two questions being altogether different. 



The endeavour of Cuvier to construct from the 

 study of fossil bones an anatomical and physiological 

 history of the individual -animal of which those bones 

 'are the sole remains, we thus see, was quite logical ; 

 but is wholly different in principle from the fallacious 

 attempt to make the facts of Ontogenesis or indivi- 

 dual embryonic development prove the validity of 

 Phylogenesis, or Evolution of the line of all living 

 forms by gradual increase and modification of struc- 

 ture throughout innumerable generations, in the 

 course of millions of years, from a spontaneously 

 produced shapeless mass of protoplasm, like a flake 

 of the white of egg. 



This leads me to the question of the influence of 

 time. It is obvious that none of the metamorphoses 

 which we can observe in the course of development 

 of the young of animals going on before us, can be 

 appealed to as having any bearing on the subject of 

 Evolution other than that of Ontogenesis as the 

 alleged recapitulation of Phylogenesis, so fully con- 

 sidered in my second lecture. Seeing that genera- 

 tions and generations innumerable are appealed to as 

 constituting fundamental conditions for the transmu- 

 tations of Evolution, the variations undergone by Mr. 



