GENETICS 



CHAPTER I 



INTRODUCTION 



1. THE IDEA OF SPECIES 



THE doctors have always disagreed regarding a 

 definition of species. What determines the exclusive 

 boundaries that shall isolate from their fellows any 

 particular group of animals or plants has long been 

 a mooted question, and still remains so. 



The Linnsean concept of a species was that of an 

 exclusive caste of individuals, inflexibly demarked, 

 over whose high barriers no nondescript tramps 

 would dare attempt to climb. When an entomolo- 

 gist of the old Linnsean school encountered an insect 

 which did not conform to the morphological tradi- 

 tions of its fellows, the frequent fate of such a non- 

 conformist was to perish under the boot-heel rather 

 than to find sanctuary in the cabinet of the preserved. 

 Since it was an exception, and a violator of the divine 

 law of the fixity of species, it deserved to be anni- 

 hilated! Those were hard days both for heretics and 

 for variations. 



The method of the older school of systematists 



1 



