392 REFLEX ACTION, INSTINCT, AND REASON 



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 vigour 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." 1 



650. "Though there is no question of absolute perfection in 

 nature, it appears that, under given conditions, adaptation is and 

 was sufficiently perfect to make it very difficult to put one's finger 

 on any defect. When we think we can do so, it generally turns 

 out that the defect is in the mind of the critic rather than in the 

 organism criticized." 2 Occasionally we are told that the palaeonto- 

 logical evidence lends support to the mutation theory in that an 

 examination of the records stored in the strata of the earth 

 indicates, as a rule, not gradual changes of type, but sudden 

 changes. The nature of this evidence may be judged by any 

 one who makes a careful examination of the cut surfaces of 

 ditches and canals. If by means of such an examination he is 

 able to achieve a knowledge of the fauna and flora now inhabiting 

 our planet sufficiently minute and detailed to enable him to 

 indicate the mode of origin of our new varieties, then, allowing 

 for the destructive effects of immensely longer time, he will have 

 some title to declare that strata deposited in past ages furnish 

 evidence of value concerning not only changes of type, but of the 

 mode of change. In that case, however, since the changes found 

 in geological strata are very vast, and since the connecting links, 

 if any, are absent, he must decide in favour, not of the hypothesis 

 that animals and plants have arisen by mutation, but in favour of 

 the hypothesis that they have arisen by special creation ; for not 

 even the most ardent mutationist will maintain, for example, that 

 marsupials suddenly gave origin to placental mammals. 



1 Op. cit. t p. 25 ;fsee also 359 of the present work. 



* Dr D. H. Scott, Presidential Address, Linnean Society, May 24th, 1909. 

 Nature, July 22nd, 1909, p. 115 ; see also 86. 



