THE PURPOSE OF YOUTH 223 



and piping chick that breaks through the shell, is a marvellous 

 prodigy. That these changes should happen at all seems so miracu- 

 lous that perhaps it would not be more surprising if they happened 

 instantaneously. It may be unphilosophical to expect it, but at 

 least it is more comfortable to our intelligence that the growth 

 of the individual does take time. When the details of the process 

 are studied minutely, they are found to be gradual and orderly ; 

 the initial piece of living matter grows and divides, and the daughter- 

 pieces divide, much in the manner of free-living cells which are not 

 going to transform themselves into more complicated creatures. 

 The first set of daughter-cells becomes arranged in a fashion closely 

 resembling the structure of simple, living creatures which do not 

 proceed beyond such a stage, and so, step by step, with at each step 

 a memory more or less definite of some free-living creature that 

 proceeds no further, the final complication of the new-born or new- 

 hatched young is reached. Again, it may be unphilosophical, but 

 it is comfortable to our intelligence, to recognise that the growth 

 of the individual is a faint reflection of the path of its ancestors 

 in the long evolution of life. The later phases of the development 

 of the individual, those that are passed through after it is hatched 

 or born, are not different in kind from the earlier or embryonic stages. 

 And so we come to see at least without surprise, if with less real 

 understanding than we are philosophically justified in claiming, 

 that living things pass through a period of childhood or youth, 

 and that that period is filled with memories of ancestral history. 



In the development of many animals these memories of the past, 

 in embryonic and in larval stages, and in the period of youth, are 

 sometimes so precise and definite that they seem to give a clear 

 picture of at least part of the ancestral history. Such instances 

 are most common in the lower animals and in the lower members 

 of the higher classes. They tend to be blurred and condensed, 

 or omitted altogether. It seems, in fact, as if the first object of 

 nature were to get rid of evidence of past evolution, and to hurry 

 through each new creature as quickly and directly as possible to 

 its adult form. 



Youth is a perilous time in the life of animals. The young things, 

 with their imperfect organs, with their relics of stages that were 

 fitted to the environment of a remote ancestor, but are out of gear 

 with existing conditions, are hampered with the cumbrous scaffolding 

 of the past and can offer feeble resistance to accidents and diseases. 

 They are a ready prey for a world of hungry enemies. It is in the 



