Statement of Weismanns System (1886). 7 



characters in kind. On the supposition that they do 

 thus differ in kind, he furnishes a very attractive 

 theory of heredity, which serves at once to explain 

 the difference, and to represent it as a matter of 

 physiological impossibility that any acquired char- 

 acter can, under any circumstances whatsoever, be 

 transmitted to progeny. 



But, in order fully to comprehend this theory, it is 

 desirable first of all to explain Professor Weismann's 

 views upon certain other topics which are intimately 

 connected with — and, indeed, logically sequent upon — 

 the use to which he puts the distinction just men- 

 tioned. 



Starting from the fact that unicellular organisms 

 multiply by fission and gemmation, he argues that, 

 aboriginally and potentially, life is immortal. For 

 when a protozoon divides itself into two more or less 

 equal parts by fission, and each of the two halves 

 thereupon grows into another protozoon, it does not 

 appear that there has been any death on the part of 

 the living material involved ; and inasmuch as this 

 process of fission goes on continuously from generation 

 to generation, there is seemingly never any death 

 on the part of such protoplasmic material, although 

 there is a continuous addition to it as the numbers 

 of individuals increase. Similarly, in the case of 

 gemmation, when a protozoon parts with a small 

 portion of its living material in the form of a bud, 

 this portion does not die, but develops into a new 

 individual ; and, therefore, the process is exactly 

 analogous to that of fission, save that a small 

 instead of a large part of the parent substance is 

 involved. Now, if life be thus immortal in the 



