Oh. VI, 8] HEREDITY AND VARIATION 315 



the study of science its great charm, and it is the chance to 

 find the answer one's self which gives to scientific investiga- 

 tion its matchless zest. 



That the organisms which now exist on the earth are 

 different from those which formerly existed, and that these 

 organisms are fitted to the conditions under which they 

 live, are two facts which have long been known to scientific 

 men, who have explained them in different ways. Thus 

 Linnaeus, and most others of the earlier naturalists, be- 

 lieved that the new kinds were each suddenly created, and 

 in very exact fitness to the surrounding conditions, by an 

 omnipotent Creator. This doctrine is known as special 

 creation. It did not, however, stand the test of advancing 

 knowledge, for ample evidence seemed to show that existent 

 kinds of organisms have developed out of earlier kinds; 

 and it seemed reasonable to suppose that in course of this 

 development the organisms and their parts became adapted 

 to their environments. This is the meaning of evolution. 

 All modern research has tended to confirm its correctness. 



The fact of evolution is one thing, and the method whereby 

 it has come about is another; and the explanation of its 

 method has been for a half century the foremost problem 

 of philosophical biology. Two great leading solutions have 

 been offered for the problem. Lamarck, a French zoologist 

 who was active a century ago, argued that the changes which 

 are known to occur in individuals, either directly by action of 

 the environment or by self-adjustment thereto, are trans- 

 mitted to the next generation and there re-appear; and 

 that thus a character can be intensified generation after 

 generation until a new kind or species results. This is the 

 View of the transmission of acquired characters. Trans- 

 lated into terms of the chromosome mechanism, it would 

 mean that any change in a character of an individual or- 

 ganism, which of course affects the cytoplasm of the cells 

 concerned, can become registered or represented in some way 

 in the determiners in its germ cells. Now of such a result 



