No. 383.] VARIATION VERSUS HEREDITY. 823 
of the long-continued action of changed conditions of life, 
without any selection, with the action of selection or mere 
accidental (so to speak) variability. I oscillate much on this 
head, but generally return to my belief that the direct action 
can have played an extremely small part in producing all the 
numberless and beautiful adaptations in every living creature ” 
(Life and Letters, vol. ii, p. 369). 
Fifteen years later, in 1876, in a letter to Moritz Wagner, 
is found the following statement : “In my opinion the greatest 
error which I have committed has been not allowing sufficient 
weight to the direct action of environment, t.e., food, climate, 
etc., independently of natural selection” (Life and Letters, 
vol. iii, p. 159); and in the following year, 1877, he wrote 
Malchior Neumayr: “ There can now be no doubt that species 
may become modified through the direct action of the environ- 
ment” (vol. iii, p. 232). The above quotations show where 
Darwin located the cause of variation, both when writing the 
Origin and in the later period of his life. 
Again, in a letter to Lyell, in 1860, we find this statement : 
“Talking of ‘Natural Selection,’ if I had to commence de 
novo, I would have used ‘natural preservation ’”’ (vol. ii, p. 346). 
And, in 1863, to Asa Gray, Darwin wrote : “I have sometimes 
almost wished that Lyell had pronounced against me. When 
I say ‘me’ I only mean change of species by descent. 
seems to me the turning point. Personally, of course, I care 
much about Natural Selection; but that seems to me utterly 
unimportant compared to the question of Creation or Modifica- 
tion” (vol. ii, p. 371). 
These letters show where Darwin placed the emphasis in 
his life work. Modification of species by descent is the great 
discovery, and natural selection and direct effects of environ- 
ment he believed to be the chief factors in bringing about this 
modification; but they were really secondary to the great fact 
of simple evolution, or the modification of organisms in the 
course of descent. 
His letters leave no doubt that what he meant by “ Natural 
Selection ” was “Natural Preservation”; the “Survival,” as 
Spencer put it, of characters which have already arisen in 
