296 SCIENTIFIC THOUGHT. 



to draw indefinitely on the great bank of time, 1 just as in 

 former ages they had been quickly brought to book by 

 existing prejudices. 2 



Whilst these contributions to the genetic view of 

 nature on the large scale were being independently 

 worked out, the sciences which deal with the minute 

 and hidden phenomena of organic growth had made great 

 progress in the same direction. Here a definite scheme 

 of development was quite evident to the most casual 

 observer. In these sciences indeed we have to do with 

 what is called in the German language " the history of 

 development " par excellence, a term which is inadequately 

 12. rendered by " Embryology " in French and English. For 



Embryol- . . 



ogy. it is an error which has frequently and for long periods 



obscured the correcter view to assume that the changes 

 and processes which characterise the development of 

 embryonic or germ life are essentially different from 

 those which exist in the larger and more complex adult 

 organism. The abolition of the fundamental distinction 

 between the processes of embryonic and of adult or full- 



1 Lyell, vol. iii. p. 358 : " Con- ical and cosmical questions in this 

 fined notions in regard to the country was Lord Kelvin. His 

 quantity of past time have tended influence belongs, however, mainly 

 more than any other prepossessions to the post-Darwinian period, and 

 to retard the progress of geology, ; begins with his celebrated memoir 



' On the Secular Cooling of the 

 Earth' (Edin. Trans., 1862, re- 

 printed in the 3rd vol. of ' Math. 



and until we habituate our- 

 selves to contemplate the possibility 

 of an indefinite lapse of ages having 

 been comprised within each of the 



and Phys. Papers,' p. 295). See 



more modern periods of the earth's | also the 2nd vol. of his ' Popular 

 history, we shall be in danger of Lectures and Addresses.' Accord- 

 forming most erroneous views in ing to the introductory statement 



geology." 



2 One of the first to attack the 



in the former paper his doubts 

 regarding the uniformitarian teach- 



uniformitarian doctrine in geology ing began as early as 1844. I shall 

 and to apply the principles of refer to these speculations at the 

 modern physical science to geolog- end of this chapter. 



