64 THE LAMARCKIAN DOCTRINE 



the question of the transmission of acquirements as presented by 

 multicellular organisms has no parallel, and can have none amongst 

 unicellular types. This distinction is clear to most students of 

 heredity, who, as a rule, maintain that parental acquirements may 

 be inherited by unicellular, but not by multicellular plants and 

 animals. Occasionally, however, some writers, chiefly medical men, 

 attempt to argue from the one question to the other ; but the 

 reasoning is obviously invalid. On the other hand, multicellular 

 organisms present a problem which, while totally distinct from the 

 question of the ' transmission ' of their acquirements, is a real 

 parallel, though seldom or never recognized as such, to the 

 problem of the 'transmission' of acquirements as presented by 

 unicellular types. We shall consider it in its proper place. 1 

 At present we must confine ourselves to the much debated 

 * transmission,' which Lamarck maintained was the source of the 

 evolution of the higher organisms. 



99. A cell-community, a multicellular plant or animal, is com- 

 pounded of germ-cells and somatic cells. The Lamarckian doctrine 

 supposes that when the somatic cells acquire characters under the 

 influence of use or injury, these acquirements so affect the germ- 

 plasm contained in the germ-cells that the cell-communities which 

 spring from them tend to reproduce the acquirements of the somatic 

 cells, not as ' acquirements,' not as direct effects of use or injury, 

 but as nutritional characters. Thus, when the muscle cells of a 

 man, for example, increase in number and power as a result of use, 

 the germ-cells dwelling within the cell-community are supposed to 

 be affected in such a remarkable and particular way that the 

 children which arise from the latter tend to develop larger and 

 more efficient muscles without the aid of use. Speaking meta- 

 phorically, the acquirements made by Brown and Jones (the somatic 

 cells) are supposed to so affect Robinson and White (the germ- 

 cells) that the descendants of the latter are characterized by traits 

 which look like those which Brown and Jones ' acquired,' but which, 

 since they are * inborn,' are really very different. Obviously this 

 power of transmuting acquirements if it exists is a very wonder- 

 ful thing, which must have arisen de novo amongst the higher types ; 

 for, as we have just seen, nothing like it occurs, or can occur, 

 amongst unicellular forms, which separate and do not form cell- 

 communities, and so cannot influence one another in this way. A 

 large and complex organism, such as man, may make a million 

 different acquirements, each of which is distinct from every other ; 



1 See 137. 



