PALAEONTOLOGY AND GEOLOGY 



enormous lengths of films containing no pictures at 

 all. And we cannot tell whether these parts are blanks 

 or whether the impression has faded from sight. Is 

 the scenario a continuous changing show or is it a 

 succession of static events'? The evidence from palae- 

 ontology is for discontinuity; only by faith and im- 

 agination is there continuity of variation. 



Embryologists, however, tell us that the imperfec- 

 tions of the palaeontological record are removed by a 

 parallel and continuous change in the embryo. The 

 embryo of the man begins as a cell, hardly to be distin- 

 guished from the first stages of other animal forms, 

 and passes through a series of changes which resemble 

 the lower forms from which he has evolved. Thus, 

 the embryo has at one stage the gills of a fish ; next, 

 the tail of a reptile; and again the placenta of an 

 early mammal. Even if we concede this argument, 

 how much do we gain'? In the short life of the em- 

 bryo, differentiation from so apparently simple a 

 form as the ovum to the final complex form must be 

 exceedingly rapid, and it is not surprising that sim- 

 ilarities of structure occur. Is it any more significant 

 that the embryo of the dog and of man can hardly 

 be distinguished than that the shell of a turtle can be 

 marked out as an articulated skeleton'? The embry- 

 ologist wishes us to take the film of the palaeontolo- 

 gist and to speed it up until the whole vast temporal 

 evolution from protoplasm to man passes before our 

 eyes in nine months. We may catch a momentary 

 glimpse now and then of similarities between the em- 



C 161 2 



