CREATION BY EVOLUTION 



from the summary of it presented in the history of the devel- 

 oping individual, and, indirectly, by comparing different ani- 

 mals with one another, a comparison that enables us to 

 deduce with reasonable accuracy their family history and 

 genealogical tree. By combining all the various lines of 

 evidence it is possible to arrive at certain perfectly definite 

 conclusions. In the first place, the size of animals has 

 increased during their evolution. None of the earliest mam- 

 mals were much bigger than a dog; creatures the size of a 

 horse or a hippopotamus were unknown. The same is true 

 of the reptiles; the giant forms appeared late in their geo- 

 logical history. The earliest forms of life were doubtless 

 microscopic. Even the smallest mammal is over a million 

 million times as large as a medium-sized amoeba. 



More important than mere increase in size is increase in 

 efficiency. No early form of life can move fast or can see 

 or hear acutely; none has a heart or a blood-system, brain or 

 nerves, jaws or limbs, or true head. The earliest true verte- 

 brates have no jaws or teeth. The earliest land vertebrates 

 could not support their bodies with their limbs. The earliest 

 members of the horse family had limbs incapable of the 

 speed achieved by the later horses, and the teeth of an early 

 horse are not nearly so efficient for grinding as those of a 

 modern horse. The brains of early mammals were barely 

 more than half the proportional size of those of present-day 

 mammals of the same bulk. The improvement of the effi- 

 ciency of separate organs is the improvement of the tools of 

 life; the improvement of the efficiency of the brain is the 

 improvement of the way in which these tools can be used. 



When we examine the geological history of a single group 

 of animals, such as the mammals or the reptiles, whose past 

 record is available to us in the fossil-bearing rocks, we find 

 that improvement in efficiency is actually made in different 



[328] 



