THE LAMARCKIAN PRINCIPLE 65 



water but that you cannot make him drink. An organism 

 selects from the materials that come in its \vay those that it 

 can digest and assimilate. A plant takes from the ground what 

 its special organisation requires. In the same way the cells in 

 the alimentary canals of the higher animals select what is suited 

 to the organism of which they form part. If a man lives entirely 

 on meat, he nevertheless extracts from it a sufficiency of certain 

 substances that he could with greater ease obtain from vegetables. 

 No organism, therefore, derives its character from its diet. No 

 form of food can exert any influence till it has first been admitted 

 to the system. And the environment cannot exercise any com- 

 pulsion ; you may make a man eat under threat of torture, but 

 the special selective cells of the alimentary canal cannot be thus 

 tyrannised over : they are the proverbial horse that cannot be 

 made to drink. They take up only what they "choose." Now 

 the germ-plasm in the reproductive cells is nourished by the soma : 

 there is no other possible source of nourishment. But the soma 

 assimilates what its congenital constitution has given it the power 

 of assimilating ; the germ-plasm has the same congenital con- 

 stitution, and how can it be modified by what is, in its nature, 

 the same as itself? 



Hence the germ-plasm cannot be freely experimented on by 

 the soma and subjected to all sorts of changes of diet. It is 

 true that the nourishment may vary as to generosity. But it is 

 easy, I believe, to over-estimate the importance of this con- 

 cession. The organism makes the reproductive cells its prime 

 care, the continuance of the species taking precedence of all 

 other objects. Hence hunger and hardship do not tell upon 

 them as they do upon the individuals who are, as it has been 

 put, the trustees of the species. It is only by assuming this, 

 that we are able to understand the rapid rebound of which, as 

 experience shows, a race is capable. They are stunted and 

 degraded by squalid conditions, yet if the children of this stunted 

 and degraded population be taken at an early age and put in a 

 better environment, the return to a better physique is astonish- 

 ingly rapid. It would be still more striking if the experiment 

 were made in the first year of infancy. 



