No. 405] 



CONSTANCY OF MUTANTS 



of plant strains which admit of the designation "Ele- 

 mentary Species" may he pardoned if he is unable to 

 accept another dogma of constancy, and is unahle to sub 

 scribe to many DeVriesian conclusions regarding the 

 comparative merits of mutation as opposed to adaptation 

 and natural survival. Most of us, T believe, can only look 

 upon a mutation as one of the types of variation through 

 which the survival process brings about evolution. T 

 believe that we still have to look for the underlying causes. 

 An ardent Darwinian can well agree to the statement : 

 "Species are derived from other species by means of 

 sudden small changes which, in some instances, may 

 scarcely be perceptible to the inexperienced eye," - hut 

 may find points of doubt and refuse to follow to the 

 limit when reading a number of statements found in the 

 same work, for example, "From their first appearance 

 they are uniform and constant."" This statement refers 

 to species. Again, "The conception of mutations agrees 

 with the old view of the constancy of species. This 

 theory assumes that a species has its birth, its lifetime, 

 and its death, even as an individual, and that throughout 

 its life it remains one and the same." 4 "Each single 

 type (be it species or subspecies or variety) is thus wholly 

 constant from its first appearance and until the time it 

 disappears either after or without the production of 

 daughter species." 5 This last sentence is certainly clear 

 to the effect that a species is never changed, at least so 

 as to affect its after progeny. It is equivalent to saying 

 that all individuals after formation in the seed remain 

 exactly like the parents and, taken with the other state- 



in argument. With this, we must assume that a man ca 



ts which insist that plants mi 

 tin constant until they change. 



means that they 



remain 



recognize ultimate 

 how many eharact 



YYhei 



'DeVries. Pla 



3 Ibid., page 9. 



4 Ibid., page 8. 



Plant Breeding. Page 9. 



