More Letters of Charles Darwin Volume I [95]
of your letter: There is nothing in my theory necessitating in each case progression of organisation, though Natural Selection tends in this line, and has generally thus acted. An animal, if it become fitted by selection to live the life, for instance, of a parasite, will generally become degraded. I have much regretted that I did not make this part of the subject clearer. I left out this and many other subjects, which I now see ought to have been introduced. I have inserted a discussion on this subject in the foreign editions. (110/7. In the third Edition a discussion on this point is added in Chapter IV.) In no case will any organic being tend to retrograde, unless such retrogradation be an advantage to its varying offspring; and it is difficult to see how going back to the structure of the unknown supposed original protozoon could ever be an advantage.
Page 13 of your letter: I have been more glad to read your discussion on "dominant" forms than any part of your letter. (110/8. Harvey writes: "Viewing organic nature in its widest aspect, I think it is unquestionable that the truly dominant races are not those of high, but those of low organisation"; and goes on to quote the potato disease, etc. In the third edition of the "Origin," page 56, a discussion is introduced defining the author's use of the term "dominant.") I can now see that I have not been cautious enough in confining my definition and meaning. I cannot say that you have altered my views. If Botrytis [Phytophthora] had exterminated the wild potato, a low form would have conquered a high; but I cannot remember that I have ever said (I am sure I never thought) that a low form would never conquer a high. I have expressly alluded to parasites half exterminating game-animals, and to the struggle for life being sometimes between forms as different as possible: for instance, between grasshoppers and herbivorous quadrupeds. Under the many conditions of life which this world affords, any group which is numerous in individuals and species and is widely distributed, may properly be called dominant. I never dreamed of considering that any one group, under all conditions and throughout the world, would be predominant. How could vertebrata be predominant under the conditions of life in which parasitic worms live? What good would their perfected senses and their intellect serve under such conditions? When I have spoken of dominant forms, it has been in relation to the multiplication of new specific forms, and the dominance of any one species has been relative generally to other members of the same group, or at least to beings exposed to similar conditions and coming into competition. But I daresay that I have not in the "Origin" made myself clear, and space has rendered it impossible. But I thank you most sincerely for your valuable remarks, though I do not agree with them.
About sudden jumps: I have no objection to them--they would aid me in some cases. All I can say is, that I went into the subject, and found no evidence to make me believe in jumps; and a good deal pointing in the other direction. You will find it difficult (page 14 of your letter) to make a marked line of separation between fertile and infertile crosses. I do not see how the apparently sudden change (for the suddenness of change in a chrysalis is of course largely only apparent) in larvae during their development throws any light on the subject.
I wish I could have made this letter better worth sending to you. I have had it copied to save you at least the intolerable trouble of reading my bad handwriting. Again I thank you for your great liberality and kindness in sending me your criticisms, and I heartily wish we were a little nearer in accord; but we must remain content to be as wide asunder as the poles, but without, thank God, any malice or other ill-feeling.
LETTER 111. TO T.H. HUXLEY.
(111/1. Dr. Asa Gray's articles in the "Atlantic Monthly," July, August, and October, 1860, were published in England as a pamphlet, and form Chapter III. in his "Darwiniana"
Page 13 of your letter: I have been more glad to read your discussion on "dominant" forms than any part of your letter. (110/8. Harvey writes: "Viewing organic nature in its widest aspect, I think it is unquestionable that the truly dominant races are not those of high, but those of low organisation"; and goes on to quote the potato disease, etc. In the third edition of the "Origin," page 56, a discussion is introduced defining the author's use of the term "dominant.") I can now see that I have not been cautious enough in confining my definition and meaning. I cannot say that you have altered my views. If Botrytis [Phytophthora] had exterminated the wild potato, a low form would have conquered a high; but I cannot remember that I have ever said (I am sure I never thought) that a low form would never conquer a high. I have expressly alluded to parasites half exterminating game-animals, and to the struggle for life being sometimes between forms as different as possible: for instance, between grasshoppers and herbivorous quadrupeds. Under the many conditions of life which this world affords, any group which is numerous in individuals and species and is widely distributed, may properly be called dominant. I never dreamed of considering that any one group, under all conditions and throughout the world, would be predominant. How could vertebrata be predominant under the conditions of life in which parasitic worms live? What good would their perfected senses and their intellect serve under such conditions? When I have spoken of dominant forms, it has been in relation to the multiplication of new specific forms, and the dominance of any one species has been relative generally to other members of the same group, or at least to beings exposed to similar conditions and coming into competition. But I daresay that I have not in the "Origin" made myself clear, and space has rendered it impossible. But I thank you most sincerely for your valuable remarks, though I do not agree with them.
About sudden jumps: I have no objection to them--they would aid me in some cases. All I can say is, that I went into the subject, and found no evidence to make me believe in jumps; and a good deal pointing in the other direction. You will find it difficult (page 14 of your letter) to make a marked line of separation between fertile and infertile crosses. I do not see how the apparently sudden change (for the suddenness of change in a chrysalis is of course largely only apparent) in larvae during their development throws any light on the subject.
I wish I could have made this letter better worth sending to you. I have had it copied to save you at least the intolerable trouble of reading my bad handwriting. Again I thank you for your great liberality and kindness in sending me your criticisms, and I heartily wish we were a little nearer in accord; but we must remain content to be as wide asunder as the poles, but without, thank God, any malice or other ill-feeling.
LETTER 111. TO T.H. HUXLEY.
(111/1. Dr. Asa Gray's articles in the "Atlantic Monthly," July, August, and October, 1860, were published in England as a pamphlet, and form Chapter III. in his "Darwiniana"