i6z THE POPULAR SCIENCE MONTHLY. 



gation in these all-important years of the beginnings of new com- 

 monwealths based upon new industries ? Millions of acres of 

 land are forever worthless without water. Who shall own the 

 streams and reservoirs a few far-sighted men, or the people 

 themselves ? Irrigation journals and conventions of irrigators 

 discuss the matter from the standpoint of the present, and en- 

 deavor to shape legislation to profitable ends. The slow, dumb 

 masses have not yet recognized the magnitude of the problems 

 involved. An effort is being made to have the United States 

 give all the arid lands to the several States and Territories in 

 which they lie, but the plan is dangerous. Only the Federal 

 Government can protect the sources of water supply; utilize, 

 reservoir, and distribute that supply, and unite water and land in 

 an indissoluble marriage bond. 



THE INADEQUACY OF " NATURAL SELECTION." 



BY HERBERT SPENCEE. 

 [Concluded.} 



THIS very pronounced opinion will be met on the part of some 

 by a no less pronounced demurrer, which involves a denial 

 of possibility. It has been of late asserted, and by many believed, 

 that inheritance of acquired characters can not occur. Weis- 

 mann, they say, has shown that there is early established in the 

 evolution of each organism, such a distinctness between those 

 component units which carry on the individual life and those 

 which are devoted to maintenance of the species, that changes in 

 the one can not affect the other. We will look closely into his 

 doctrine. 



Basing his argument on the principle of the physiological 

 division of labor, and assuming that the primary division of labor 

 is that between such part of an organism as carries on individual 

 life and such part as is reserved for the production of other lives, 

 Weismann, starting with " the first multicellular organism," says 

 that " Hence the single group would come to be divided into two 

 groups of cells, which may be called somatic and reproductive 

 the cells of the body as opposed to those which are concerned with 

 reproduction" (Essays upon Heredity, p. 27). 



Though he admits that this differentiation " was not at first 

 absolute, and indeed is not always so to-day," yet he holds that 

 the differentiation eventually becomes absolute in the sense that 

 the somatic cells, or those which compose the body at large, come 

 to have only a limited power of cell-division, instead of an un- 

 limited power which the reproductive cells have ; and also in the 



