HERITAGE OF THE INDIVIDUAL 267 



reactions to the environment on the destinies of the race, 

 even though they see, at present, no grounds for a belief that 

 any specific modification can enter the heritage and so be 

 reproduced. 



In this connection the question of the inheritance of disease 

 will undoubtedly arise in the reader's mind. But this is really 

 not a special case. If the disease is the result of a defect 

 in the germinal constitution, it may be inherited just as any 

 other character, physiological or morphological. But if the 

 disease is a disturbance set up in the body by some exigencies 

 of life or through infections by specific micro-organisms, be- 

 fore birth or later, inheritance does not occur; though it is 

 well known that susceptibility or immunity to disease-pro- 

 ducing organisms the 'soil' for their development may be 

 inherited. It may, however, be suggested in passing that 

 from the standpoint of the individual born malformed, struc- 

 turally or mentally, as a result of parental alcoholism or other 

 obliquities, it probably will not appear of the first moment 

 that the sins have been visited otherwise than by actual 

 inheritance. 



The whole question of the nonheritabilitjr of modifications 

 or acquired characters is a relatively new point of view which 

 has been fostered by an ever-increasing appreciation of the 

 details of the chromosome mechanism of inheritance, and the 

 realization of the essential truth of Weismann's contrast of 

 the soma and germ. Indeed, Lamarck did not question the 

 inheritance of acquired characters and made it the corner- 

 stone of his theory of evolution, while some have even gone 

 so far as to say that either there has been inheritance of ac- 

 quired characters, or there has been no evolution. But the 

 question is not so serious as that, as will be seen later on; 

 though it obviously is profoundly important from many 

 viewpoints, biological, educational, and sociological. 



