66 EVOLUTION 



that involve disputed points. Whether the bat got 

 its wings gradually on the lines of Lamarck's, Darwin's, 

 or Weismann's theory, or more rapidly, by large 

 changes, we shall not need to determine. But the 

 reader will avoid confusion by remembering that it is 

 only in this secondary sense that Darwinism is "dis- 

 puted" or "abandoned." Charles Darwin's son is one 

 of the most distinguished supporters of the mutation 

 theory. In point of fact it would be a great advantage 

 in the story of evolution to know that certain new 

 structures or features were somewhat suddenly de- 

 veloped. It is precisely the early (and almost useless) 

 stages of useful organs that chiefly puzzle the evolu- 

 tionist. If we may imagine that violent changes in the 

 earth's story the flooding of districts owing to a sinking 

 of level, or the occurrence of an ice-age threw species 

 into confusion and led to mixed breeding, and this led to 

 mutations, the work is easier. But I am constrained to 

 warn the reader that " mutations " have only been 

 observed in a few cases, and those mostly of the vegetal 

 world, so that it is precarious as yet to make a system 

 of them. 



We may now return to our primitive ocean, and take 

 up once more the story of the evolution of life. Again 

 we must have recourse to careful speculation in studying 

 the earlier development of the animal world. Not until 

 the animal had developed hard or tough parts could its 

 remains be preserved in the mud or sand at the floor of 

 the sea, and it passed through numbers of forms before it 

 reached this stage. Moreover, the earliest remains that 

 were preserved have apparently been charred into mere 

 masses of graphite or ground into shapeless limestone. 

 When the first fossils appear, the story of development 



