94 THE FIRST PRINCIPLES OF HEREDITY 



the race and maintains it, Darwin himself still upheld at 

 the side of Natural Selection the Lamarckian principle to 

 a considerable extent. Nay, his theory of Pangenesis, as 

 we have seen, was mainly conceived with the idea of ex- 

 plaining the method by which modifications undergone by 

 the parent through environmental changes could be trans- 

 mitted to the germ-cells, and thus lead to their inheritance 

 by the next generation. We have already pointed out 

 some objections against this theory. Here we may add 

 that, even if we take the mode of transmission of acquired 

 characters for granted, we are still far from a solution of 

 the problem. For if the cells of the bod}^ throw off charac- 

 teristic gemmules at all stages of their existence, gemmules 

 representing all these stages would accumulate in the germ- 

 cells, and it is difHcult to conceive how special impressions 

 made by environmental conditions should be pre-eminent, 

 and be repeated by the germ-cells in exactly the same 

 manner. One would rather expect a general effect of aU 

 the influences registered than particulate inheritance of 

 special modifications. Other theories have been advanced 

 by the adherents of the belief in Use-inheritance (as the 

 theory of the inheritance of acquired characters has shortly 

 been called), for instance, by Herbert Spencer, whose 

 system we have already dealt with. 



But the theory par excellence of this school of thought 

 is the " Mnemik Theory," first propounded by E. Hering 

 in Germany, and independently by Samuel Butler in 

 England. According to this theory, the cells and tissues 

 of the organism retain impressions impinging on them by 

 means of the organic memory, unconscious though it be, 

 which is the attribute of all living matter. The modifica- 

 tions wrought on the body reverberate through the body 

 to the germ-cells, and are there retained as a faint echo, as 

 it were, by means of the mnemic faculty of the germ-cells, 

 which are thus modified in accordance with the original 

 impress on the body. Whether this is so or not, it does not 

 solve the problem under discussion. An explanation of 



