62 THE SURVIVAL OF THE UNLIKE. [ll, 



specific function of reproduction, or eventually became 

 elements of sex. As organisms became more complex in 

 their structure, there came to be great differences be- 

 tween this reproductive or germ portion and the sur- 

 rounding or body portion ; and Weismann assumes that 

 these two elements are different and distinct from each 

 other in kind, and, inasmuch as the one -celled organisms 

 propagated their exact kind by simple division, that 

 therefore the reproductive elements of the many -celled 

 or complex body must continue to perpetuate their kind 

 or enjoy immortality, while all the surrounding or body 

 cells die and are reproduced only through the recon- 

 structive power of the sexual elements. There are, then, 

 according to this hypothesis, two elements or plasms in 

 every organized being, the germ -plasm and the soma- 

 plasm or body -plasm; and every organism which pro- 

 creates thereby preserves its germ -plasm to future gen- 

 erations, while death destroys the remainder. A vital 

 point in this hypothesis is the method by which the 

 soma-plasm, or the organs and body of the organism, 

 can be so impressed upon the germ that they shall be- 

 come hereditary. At first it would seem as if some as- 

 sumption like that of Darwin's might be useful here — 

 that this germ -plasm is impressed by particles thrown 

 off from all the surrounding or soma-cells; but this 

 Weismann considers to be too unwieldy, and he ascribes 

 the transfer of these characters through the medium of 

 the germ -plasm to "variations in its molecular consti- 

 tution." In other words, there can be no heredity of a 

 character which originates at the periphery of the indi- 

 vidual, because there is no means of transferring its 

 likeness to the germ. All modification of the offspring 

 is predetermined in the germ -plasm; and if the new 



