INSTINCT 217 



the bird. Enclosed in the larger end of the egg is a 

 supply of air for the chick. On the end of the upper 

 mandible of the chick is developed a hard point, 

 with which it bores through the shell. These several 

 points of structure co-operate with the instincts of 

 the mother in the development of the chick and its 

 escape from the shell. 



I have already dwelt sufficiently on the difficulties 

 involved in trying to account by evolution for the 

 ■existence of instincts and the adaptations to them 

 which are necessary in the structure of the organism. 



Instinct is blind and knows not the end for which 

 it works. It cannot be improved by the experience 

 of the individual, and consequently there is no gain 

 by which heredity may profit. Mr. Darwin admits 

 that "it can be clearly shown that the most wonder- 

 ful instincts with which we are acquainted, namely, 

 those of the hive-bee and of many ants, could not 

 possibly have been acquired by habit." * 



He refers their origin to " the natural selection of 

 what may be called spontaneous variations of in- 

 stincts;" but he also thinks that " use or habit " has 

 been a factor in the origin of instincts. 



If, however, " the most wonderful instincts"" 

 "could not possibly have been acquired by habit," 

 we must look for their origin to " spontaneous varia- 

 tions." 



Thus, not only the origination but the perfecting 

 of the most highly-developed' instincts is left to 

 chance, and, in the case of neuter insects, without the 

 aid of heredity. I think it impossible that the great 

 number of instincts, together with the multitude of 

 peculiarities of structures in animals, which render 

 it possible for the instincts to be of use, could have 

 thus been produced. 



* Origin of Species, p. 202. 



