EVOLUTION OF MAN 35 



instance, is there that the ancestor of man possessed 

 a variation in the power of acquiring the upright 

 position, independently of the attempt to walk on 

 his hind legs ? 



Dr. Reid supposes that this power of making 

 acquirements is greatest among the higher animals, 

 and little or not at all present in the lower animals 

 and plants. He instances the frog, and expresses 

 his belief that a tadpole enclosed in a hole or crevice, 

 if supplied with food, would develop into a perfect 

 frog, and that this is possibly the explanation of those 

 cases reported in the newspapers from time to time 

 of perfect frogs found enclosed in stone in quarries. 

 It is unnecessary to discuss seriously this suggestion ; 

 it will be sufficient to consider how much foundation 

 there is for the dictum of Dr. Reid that the frog's 

 body gains nothing from use, and its mind almost 

 nothing from experience. This implies that the 

 metamorphosis is entirely due to heredity and not at 

 all to stimulation. It has been proved, on the con- 

 trary, that aquatic larvae of Amphibians can be 

 made to retain the larval state by forcing them to 

 breathe in the water and not allowing them to breathe 

 air, so that in this case, as in many others, the develop- 

 ment is partly due to acquirement in Dr. Reid's 

 sense of the term. Dr. Reid contrasts with the 

 supposed development of the frog the alleged fact that 

 if the limb of an infant be locked by paralysis or by 

 a joint disease it does not develop into an adult 

 limb, but there is every reason to believe that the 

 same statement would be true of the frog. 



