116 EVOLUTION 



ducer of the child. In a new sense the child 

 is " a chip of the old block." The clarifying 

 and corroboration of this doctrine of germinal 

 continuity has been one of the most important 

 steps of post-Darwinian biology. It enables 

 us to understand why like tends to beget like; 

 and it also suggests, what is hardly less impor- 

 tant, that the new departures or variations, 

 which we have spoken of as individual, are 

 really expressions of the changeful vitality of 

 the undying germ-plasm. As Bergson puts it : 

 44 Life is like a current passing from germ to 

 germ through the medium of a developed 

 organism. . . . The essential thing is the 

 continuous progress indefinitely pursued, 

 an invisible progress, on which each visible 

 organism rides during the short interval of 

 time given it to live." 



ORGANIC CHANGES ANALYZED. Great pro- 

 gress has been made in recent years in studying 

 the individual peculiarities of plants and 

 animals, in registering their amount and their 

 frequency. The collection and analysis of 

 these " biometric " data is of fundamental 

 importance, for the Darwinian method of 

 interpretation is like that of Lyell, throwing 

 the light of the present on the darkness of the 

 past; and it is only when we know securely 

 what changes are going on now that we can 



