304 The Field Naturalist's Quarterly November 



It is to be particularly noted that according to this 

 view the cause of the variation in the lizard is something 

 extraneous to itself — its environment, in the first place, — 

 and that the variation having once occurred, is transmitted 

 by the influence of what is called heredity. 



On the other hand, according to the Darwinian view, 

 the initial factor in the variation of the four-limbed lizard 

 is not to be sought for in extraneous circumstances such 

 as environment, but in the inherent nature of animal life. 

 All admit that the variations take place, but the newer 

 theory is that these variations arise spontaneously. That 

 does not mean that they arose in a haphazard way 

 necessarily, but that they are the result of the operation 

 of a law concerning which we know nothing. It means 

 that it is the property of germ plasm to vary, whether the 

 environment changes or not. The result of these variations 

 may be useful to the creature or otherwise. In this case, 

 if one of these spontaneous variations in the lizard took the 

 shape of a reduction in the size of the limbs at a time when 

 limbs were rather in the way than otherwise, then that 

 variation would confer an advantage upon those individuals 

 in which it occurred. If their life depended upon being 

 able to burrow or otherwise protect themselves in some 

 special way which limbs interfered with, it is obvious that 

 the members of the race which had this new character would 

 be the survivors in the struggle for life. If the circumstances 

 which made this a useful variation continued in operation, 

 those which had not thus varied would in time become 

 exterminated. The offspring of the lizards with the 

 reduced limbs would also have this character, some to a 

 greater degree than others, and those in which it was most 

 marked would in their turn survive. They would vary in 

 their turn, and so the process would finally result again in a 

 species of lizard without limbs. In this case the spontaneous 

 variations have in some instances been adapted to the 

 environment of the creature, and therefore have conferred 

 upon it a commanding advantage, enabling it to survive 

 where others have become exterminated. The environment 

 has not caused the variation during the life of any given 

 members of the species, but these members have given rise 



