138 HYPOTHESIS OF THE DEVELOPMENT OF 



algae and fungi water and land plants. Still, to keep the 

 axiom whole, these are held in doubt, or relegated to a place 

 in the elastic region of the varieties. Such is the stage which 

 we have now attained. But this is a process the reverse of 

 philosophical : it is to start with a theory, and then make 

 facts succumb to it. Were the process reversed and the facts 

 taken first, we should see that a great modifiability exists in 

 organic nature, especially in the humbler departments of the 

 two kingdoms. And seeing that this modifiability presents 

 itself within the scope of a very limited experience, it might 

 safely be inferred that something much greater would be de- 

 tected if our range of experience were extended, especially 

 since the world presents us with results which can only be 

 naturally accounted for in this manner. It is here a fact to 

 be specially remarked, that the greatest variability, the most 

 striking instances of transition or intercommunion of forms, 

 are offered in the lower grades of being. In these depart- 

 ments of nature, generation is rapid and abundant in compa- 

 rison with the reproduction of the higher forms. What 

 requires perhaps a century in the one case (say a series of 

 three generations) will be accomplished in a day in the 

 other. Nothing, therefore, seems more natural than that phe- 

 nomena connected with the reproduction of the higher 

 animals should require a much longer time to be evolved than 

 those connected with the lower. The time may be, in the 

 one case, such as to fall within our range of observation (and 

 this range, as far as scientific accuracy is concerned, is but a 

 day), while in the other case it may be, and indeed, on a just 

 comparison, we should expect it to be, beyond even the whole 

 space of what is called the historical era. Such is precisely 

 the point to which the present theory would lead us. We 

 see that permanency of specific distinctions in the higher or- 

 ganisms would sink, as it has done in so many of the lower, 

 if we had as long a time to observe their reproductive history as 

 would, in embryology, be equivalent to the space of time during 

 which we have observed the humbler creatures. We see this 

 persistency and think it fixed, exactly as men have hitherto 

 seen the solar position in the universe. We advance among 



