The Problem of Adaptation 25 



seed-feeding birds or mammals. Shall we try to account for 

 its color on the grounds of the poisonous character of the 

 seed ? Has it been acquired as a warning to those animals 

 that have eaten it once, and been made sick or have died in 

 consequence ? I confess to a personal repugnance to imag- 

 inative explanations of this sort, that have no facts of experi- 

 ence to support them. 



Changes in the Organism that are of No Use to the 

 Individual or to the Race 



As an example of a change in the organism that is of no 

 use to it may be cited the case of the turning white of the 

 hair in old age in man and in several other mammals. The 

 absorption of bone at the angle of the chin in man, is another 

 case of a change of no immediate use to the individual. We 

 also find in many other changes that accompany old age, 

 processes going on that are of no use to the organism, and 

 which may, in the end, be the cause of its death. Such 

 changes, for instance, as the loss of the vigor of the muscles, 

 and of the nervous system, the weakening of the heart, and 

 partial failure of many of the organs to carry out their 

 functions. These changes lead sooner or later to the death 

 of the animal, in consequence of the breaking down of some 

 one essential organ, or to disease getting an easier foot- 

 hold in the body. We have already discussed the possible 

 relation of death as an adaptation, but the changes just men- 

 tioned take place independently of their relation to the death 

 of the organism as a whole, and show that some of the nor- 

 mal organic processes are not for the good of the individual 

 or of the race. In fact, the perversions of some of the most 

 deeply seated instincts of the species, as in infanticide, while 

 the outcome of definite processes in the organism, are of 

 obvious disadvantage to the individual, and the perversion of 

 so deeply seated a process as the maternal instinct, leading 



