xvi PREFACE 



after forming the brain, play upon the nervous 

 fibres like the wind on the harp, is an interesting 

 conception, no less so is the attempt to explain the 

 inheritance of the qualities acquired by the trophic 

 influence of the nervous system. 



Certainly the attempt is somewhat premature. 

 We are in want of anatomico-physiological data to 

 prove how an organ made perfect by adaptation to 

 the conditions of its environment can so influence 

 the brain that the latter in its turn modifies the 

 germinal cells. Nor are there wanting savants 

 like Weissman who roundly deny the trans- 

 missibility of the acquired characteristics, imputing 

 all to the chance elements of variation and natural 

 selection. But, in fine, if the arduous problem has 

 not at the moment obtained a complete solution, it 

 is something to know that our ideas and feelings 

 exert an influence, by means of the great organ of 

 sympathy, upon the nutrition of the glands and the 

 molecular architecture of the germinal cells. At 

 all events, the aim is a tempting one, and if science 

 ultimately confirms this principle (the action of the 

 nervous system upon the molecular adjustment of 

 the nucleus and the protoplasm), the nerve theory 

 of the inheritance of acquired qualities will replace 

 the arbitrary hypothesis of Darwin, Haeckel, 

 De Wries, and others on such an interesting 

 problem. 



