264 DARWINISM TO-DAY. 



destructive criticism of about all the evidence of observa- 

 tion which has been offered in behalf of it. And yet just at 

 the present time do biologists recognise more keenly than ever 

 the need and relief the actuality of such inheritance would 

 give them in their attempts to solve the great problems of 

 adaptation and species-forming? I cannot undertake to say 

 whether more reputable biologists disbelieve in than believe 

 in the existence of such inheritance, but it is obvious that 

 the disbelievers have the present prestige of apparent vic- 

 tory : they call for convincing evidence of such inheritance, 

 and it is not produced. On the other hand, there are many 

 reputable, thoughtful, honest, actively working biologists and 

 paleontologists (particularly many palaeontologists in pro- 

 portion to the total number of palseontological students) who 

 say, although not loudly and even a bit shamefacedly, per- 

 haps, that they must believe in the possibility and the actu- 

 ality of this inheritance; there is no getting forward with- 

 out it. 



In taking up our brief exposition of Lamarckism, let me 

 say first that only in post-Darwinian years has Lamarckism 

 been put so strongly in contrast with Darwinism as it has. 

 Darwin himself included part of Lamarckism as a minor 

 factor or influence in his explanation of adaptation and 

 species-forming, and Plate, in the recent most notable criti- 

 cal discussion of Darwinism, takes nearly exactly the old 

 ground of Darw r in, namely, an acceptance of the inheritance, 

 in some degree and under some conditions, of acquired 

 characters, and the consequent possibility of a certain 

 amount of Lamarckian orthogenesis, i. e., an orthogenesis 

 due to the inheritance of the results of use, disuse, and func- 

 tional stimuli. It is only neo-Darwinism (of Weismann, 

 Wallace, and others) and neo-Lamarckism (of Spencer, 

 Packard, and others) that are so radically opposed, so mutu- 

 ally exclusive. 



That an animal in its lifetime, and especially during its 



