Mayr 
"... It is a considerable strain on one's credulity to assume that finely balanced systems such
 as certain sense organs (the eye of vertebrates, or the bird's feather) could be improved upon by random mutations." 
Nilsson
 "... Therefore mutations are never found in nature (e.g. not a single one of the several hundreds 
of Drosophila Mutations), and therefore they are able to appear only in the favorable environment 
of the experimental field or laboratory..." 
Dobzhansky 
"A majority of mutations, both those arising in the laboratories and those stored in natural 
populations produce deteriorations of the viability, hereditary disease and monstrosities. 
Such changes it would seem, can hardly serve as evolutionary building blocks." 

Increased Mutation Rate 
The poor Fruit Fly (Drosophila) has been radiated, heated, gassed and tortured in all imaginable
 ways for nearly a hundred years - increased mutation rates of 15,000% - not a single beneficial 
change observed. But thousands of bizarre changes have been created and most often the result has
 been dead Fruit Flies.