126 HYPOTHESIS OF THE DEVELOPMENT OF 



time which have been described. Suppose that an ephe- 

 meron, hovering over a pool for its one April day of life, 

 were capable of observing the fry of the frog in the water 

 below. In its aged afternoon, having seen no change upon 

 them for such a long time, it would be little qualified to con- 

 ceive that the external branchiae of these creatures were to 

 decay, and be replaced by internal lungs, that feet were to be 

 developed, the tail erased, and the animal then to become a 

 denizen of the land. Precisely such may be our difficulty in 

 conceiving that plants and animals are capable of advancing 

 by generation to a higher type of being. Granting that, 

 during the whole time which we call the historical era, there 

 have been no movements of this kind, nor even any of the 

 less rare transitions in which only specific modifications are 

 concerned, we know the historical era to be only an infinitesi- 

 mal portion of the entire age of our globe. We do not know 

 what may have happened during the ages which preceded 

 its commencement, as we do not know what may happen in 

 ages yet in the distant future. All, therefore, that we can 

 properly infer from the apparent fixity of organic forms is, 

 that such is the ordinary procedure of nature in the time im- 

 mediately passing before our eyes. Mr. Babbage's illustra- 

 tion enables us to understand how this ordinary procedure 

 may be subordinate to a higher law which in proper season 

 interrupts and changes it. 



It has been seen that, in the reproduction of the higher 

 animals, the new being passes through stages in which it is 

 successively fish-like and reptile-like. But the resemblance 

 is not to the adult fish or the adult reptile, but to the fish and 

 reptile at a certain point in their fetal progress ; this holds 

 true with regard to the vascular, nervous, and other systems 

 alike. It seems as if gestation consisted of two distinct and 

 independent stages one devoted to the developme/it of the 

 new being through the conditions of the inferior types, or, 

 rather through the corresponding first stages of their develop- 

 ment; another perfecting and bringing the new being to a 

 healthy maturity, on the basis of the point of development 



