254 GEOEGE JOHN EOMANES 1890 



February 16, 1890. 



After receiving your letter this day a month ago, 

 it occurred to me that I had better write an article in 

 ' Nature ' on Panmixia, pointing out the resemblances 

 and the differences between Weismann's statement 

 of the principle and mine. Shortly after sending it 

 in, Weismann's answer to Vines appeared, and from 

 this it seems that he has modified his views upon the 

 subject. For while in his essays he says that ' the 

 complete disappearance of a rudimentary organ can 

 only take place by the operation of natural selection ' 

 (i.e. reversal of selection through economy, &c.), in 

 ' Nature ' he says, ' Organs no longer in use become 

 rudimentary, and must finally disappear, solely by 

 Panmixia.' Thus, the same facts are attributed at 

 one time ' only ' to the presence of selection, and at 

 another time ' solely ' to its absence. 



Now, the latter view seems exactly the same as 

 mine, if it means (as I suppose it must) that the 

 cessation of selection ultimately leads to a failure of 

 heredity. (How about stability of germ-plasm here ?) 

 The time during which the force of heredity viHl per- 

 sist, when thus merely left to itself, will vary with the 

 original strength of this force, which, in turn, will 

 presumably vary with the length of time that the 

 organ has previously been inherited. Thus, differences 

 of merely specific value (to which you allude in your 

 letter) will quickly disappear under cessation of 

 selection, while ' vestiges ' of class value are long- 

 enduring. The point to be clear about is that the 

 cessation of selection (in my view) entails two conse- 

 quences, which are quite distinct. First, a compara- 



