

SECTION III. 

 EVOLUTIONAEY HYPOTHESES. 



CHAPTER I. 



THE PRINCIPAL ATTEMPTS AT EXPLANATION HITHERTO. 



MUCH of that which we shall say in the following 

 pages regarding the evolutionary hypotheses already 

 put forward has only an historical value. An oppor- 

 tunity, however, thereby presents itself for learning 

 the nature of the evidence by which it has been 

 attempted to establish the theory of evolution as 

 opposed to that of constancy. The refutation of the 

 theory of the unchangeability of the systematic species, 

 which with Lamarck was hardly much more than a 

 simple denial, constitutes the one permanent result 

 of the best known of all theories of evolution termed 

 Darwinism and Lamarckism. 



1. Lamarckism and neo-Lamarckism* 

 (1) The original doctrine of Lamarck. 



(i) Short description. Jean Baptiste Chevalier de 

 Lamarck (1744 to 1829) published in the year 1809 a 

 work entitled ' Philosophic Zoologique/ in which, for 

 the first time, the unchangeability of organisms was 

 entirely denied, and the development of the present 

 organic world from inorganic matter by spontaneous 



