The Pangcncs. 645 



Ninncvical changes of the f^augenes arc therefore the 

 basis of fluctuating variability. Changes in the position 

 of the pangoie in the nucleus lead to retrogressive and 

 degressive mutations, ivhilst to account for progressive 

 mutation zee must assume the for unit ion of new types 

 of pangenes. 



The facts which have heen descriljcd in iliis work, 

 conform to this hypotliesis so closely that tlicv niav he 

 regarded as proofs of the truth of the princii)le. It 

 seems desirahle to deal further with this point without, 

 however, elahorating" suhsidiary hypotheses. 



Mendel^s discovery goes far to support the theory 

 of independent bearers of hereditary characters. Their 

 independence stands out more clearly in this case than in 

 any other, Avith the exception of the process of mutation 

 itself. In my first preliminary note on this subject T 

 have pointed out the great importance of his laws in their 

 bearing on the doctrine of pangenesis ; and since that 

 time CoRRENS, Bateson, Cuenot and many other auth(jrs 

 have more or less subscribed to this view. Cu exot. wlio. 

 with Bateson, was the first to demonstrate the applica- 

 l)ility of Mendel's laws to the animal kingdom, calls the 

 units wliich are concerned in these crosses '^particules 

 representatives.^''^ Whether these factors themselves are 

 the pangenes of the nuclear tlu'eads, or whether these 

 factors are composed of groups of similar units, is a 

 highlv important question which, however, can only be 

 decided l)v means of future ex]U'riments. 



For, as Bateson j^oints out. it is still iic^ssiblc th:it 

 the constant Mendelian Inl^rid races are not absohitely 

 ])ure with regard to their individual characters: that is 



'T.. CuKNOT. La In'i dr Mendel cl rin'rciiiti' dc la f^iginnttatiui 

 rhc: Irs soitris. Arch. xool. cxpcrim. ct fjonoralc. T002. No. 2. 



