II THE PROGRESS OF SCIENCE 119 



geological epoch has been obtained. Physical 

 science has thus been brought into the closest 

 relation with history and with archaeology; and 

 the striking investigations which, during our 

 time, have put beyond doubt the vast antiquity 

 of Babylonian and Egyptian civilisation, are in 

 perfect harmony with the conclusions of anthro- 

 pology as to the antiquity of the human species. 



Classification is a logical process which consists 

 in putting together those things which are like 

 and keeping asunder those which are unlike ; and 

 a morphological classification, of course, takes note 

 only of morphological likeness and unlikeness. 

 So long, therefore, as our morphological knowledge 

 was almost wholly confined to anatomy, the char- 

 acters of groups were solely anatomical ; but as 

 the phenomena of embryology were explored, the 

 likeness and unlikeness of individual development 

 had to be taken into account ; and, at present, the 

 study of ancestral evolution introduces a new ele- 

 ment of likeness and unlikeness which is not only 

 eminently deserving of recognition, but must 

 ultimately predominate over all others. A classi- 

 fication which shall represent the process of 

 ancestral evolution is, in fact, the end which the 

 labours of the philosophical taxonomist must keep 

 in view. But it is an end which cannot be at- 

 tained until the progress of palaeontology has 

 given us far more insight, than we yet possess, in- 

 to the historical facts of the case. Much of the 



