[19]Darwinism, p. 169.
[19]Darwinism, p. 169.
[20]Origin of Species, p. 136.
[20]Origin of Species, p. 136.
[21]Darwinism, p. 152.
[21]Darwinism, p. 152.
[22]Origin of Species, pp. 44, 45.
[22]Origin of Species, pp. 44, 45.
[23]Origin of Species, ed. 6, pp. 134, 135.
[23]Origin of Species, ed. 6, pp. 134, 135.
[24]Archives des Sciences physiques et naturelles(Genève), vol. liii. (1875), pp. 211-236.
[24]Archives des Sciences physiques et naturelles(Genève), vol. liii. (1875), pp. 211-236.
[25]Remarques sur le fait de l'existence en société à l'état sauvage des espèces végétales affines et sur d'autres faits relatifs à la question de l'espèce, par Alexis Jordan; lues au congrès de l'Association Française pour l'Avancemeat des Sciences, 2me session, Lyon, séance de 28 Août, 1873.
[25]Remarques sur le fait de l'existence en société à l'état sauvage des espèces végétales affines et sur d'autres faits relatifs à la question de l'espèce, par Alexis Jordan; lues au congrès de l'Association Française pour l'Avancemeat des Sciences, 2me session, Lyon, séance de 28 Août, 1873.
[26]Evolution and its Relations to Religious Thought, &c. pp. 236-7.
[26]Evolution and its Relations to Religious Thought, &c. pp. 236-7.
[27]Life and Letters, vol. ii. p. 28.
[27]Life and Letters, vol. ii. p. 28.
[28]Ibid.
[28]Ibid.
[29]Origin of Species, p. 80, 6th ed. (1872).
[29]Origin of Species, p. 80, 6th ed. (1872).
[30]Life and Letters, vol. iii. p. 158.
[30]Life and Letters, vol. iii. p. 158.
[31]Ibid.p. 159.
[31]Ibid.p. 159.
[32]Ibid.p. 160.
[32]Ibid.p. 160.
[33]The analogy is radically unsound because unconscious selection differs from methodical selection only in thedegreeof "separation" which it effects. These two forms of selection do not necessarily differ from one another in regard to thenumberof characters which are being simultaneously diversified; for while it may be the object of methodical selection to breed for modification of a single character alone, it may, on the other hand, be the result of unconscious selection to diversify an originally uniform stock, as Darwin himself observes with regard to horse-breeding. The real distinction between monotypic and polytypic evolution is, not at all with reference to thedegreeof isolation (i. e.amountof "separation"), but to thenumber of casesin which any efficient degree of it occurs (i. e. whether in but a single case, or in two or more cases).
[33]The analogy is radically unsound because unconscious selection differs from methodical selection only in thedegreeof "separation" which it effects. These two forms of selection do not necessarily differ from one another in regard to thenumberof characters which are being simultaneously diversified; for while it may be the object of methodical selection to breed for modification of a single character alone, it may, on the other hand, be the result of unconscious selection to diversify an originally uniform stock, as Darwin himself observes with regard to horse-breeding. The real distinction between monotypic and polytypic evolution is, not at all with reference to thedegreeof isolation (i. e.amountof "separation"), but to thenumber of casesin which any efficient degree of it occurs (i. e. whether in but a single case, or in two or more cases).
[34]Life and Letters, vol. iii. pp. 157-8.
[34]Life and Letters, vol. iii. pp. 157-8.
[35]Ibid.pp. 157-8.
[35]Ibid.pp. 157-8.
[36]Life and Letters, vol. iii. p. 161.
[36]Life and Letters, vol. iii. p. 161.
[37]Page 81. The three forms of isolation mentioned are, "from haunting different stations, from breeding at slightly different seasons, or from the individuals of each variety preferring to pair together."
[37]Page 81. The three forms of isolation mentioned are, "from haunting different stations, from breeding at slightly different seasons, or from the individuals of each variety preferring to pair together."
[38]Life and Letters, vol. iii. p. 159.
[38]Life and Letters, vol. iii. p. 159.
[39]Life and Letters, vol. iii. p. 155.
[39]Life and Letters, vol. iii. p. 155.
[40]Variation, &c., vol. ii. p. 262.
[40]Variation, &c., vol. ii. p. 262.
[41]Life and Letters, vol. iii. p. 161.
[41]Life and Letters, vol. iii. p. 161.
[42]Die Darwin'sche Theorie und das Migrationsgesetz(1868):Ueber den Einfluss der geographischen Isolirung, &c. (1870).
[42]Die Darwin'sche Theorie und das Migrationsgesetz(1868):Ueber den Einfluss der geographischen Isolirung, &c. (1870).
[43]For instance, speaking of common, or continuous areas, he says:—"In this case a constant variety, or new species, cannot be produced, because the free crossing of a new variety with the old unaltered stock will always cause it to revert to the original type; in other words, will destroy the new form. The formation of a real variety, which Darwin, as we know, regards as the commencement of a new species, will only succeed when a few individuals, having crossed the barrier of their habitat, are able to separate themselves for a long time from the old stock." And the last sentence, given as a summary of his whole doctrine, is—"The geographical isolation of the form, a necessary consequence of migration, is the cause of its typical character."
[43]For instance, speaking of common, or continuous areas, he says:—"In this case a constant variety, or new species, cannot be produced, because the free crossing of a new variety with the old unaltered stock will always cause it to revert to the original type; in other words, will destroy the new form. The formation of a real variety, which Darwin, as we know, regards as the commencement of a new species, will only succeed when a few individuals, having crossed the barrier of their habitat, are able to separate themselves for a long time from the old stock." And the last sentence, given as a summary of his whole doctrine, is—"The geographical isolation of the form, a necessary consequence of migration, is the cause of its typical character."
[44]Ueber den Einfluss der Isolirung auf die Artbildung(1872).
[44]Ueber den Einfluss der Isolirung auf die Artbildung(1872).
[45]Loc. cit., p. 43.
[45]Loc. cit., p. 43.
[46]Physiological Selection, pp. 348, 389.
[46]Physiological Selection, pp. 348, 389.
[47]Loc. cit., p. 54.
[47]Loc. cit., p. 54.
[48]Nature, vol. xliii. p. 410, and vol. xliv. p. 29.
[48]Nature, vol. xliii. p. 410, and vol. xliv. p. 29.
[49]Darwinism, p. 143.
[49]Darwinism, p. 143.
[50]In Appendix to H. M. Stanley'sHow I found Livingstone, 2nd ed. London, 1872, p. 715.
[50]In Appendix to H. M. Stanley'sHow I found Livingstone, 2nd ed. London, 1872, p. 715.
[51]Animal Life and Intelligence, pp. 98, 99 (1890-1891).
[51]Animal Life and Intelligence, pp. 98, 99 (1890-1891).
[52]The Factors of Evolution(1891).
[52]The Factors of Evolution(1891).
[53]Darwinism, p. 151.
[53]Darwinism, p. 151.
[54]Ibid.
[54]Ibid.
[55]Loc. cit., p. 151.
[55]Loc. cit., p. 151.
[56]Namely,Lycaena denzelii,L. pheretes,Argynnis pales,Erebia mante.
[56]Namely,Lycaena denzelii,L. pheretes,Argynnis pales,Erebia mante.
[57]Since the above was written, I have heard of some cases which seem to present greater difficulties to our theory than those above quoted. These refer to some of the numerous species of land mollusca which inhabit the isolated rocks near Madeira (Dezertas). My informant is Dr. Grabham, who has himself investigated the matter, and reports as follows:—"It is no uncommon thing to meet with examples of the same species, sub-fossil, recent, and living upon one spot, and presenting no variation in the long record of descent." Then, after naming these examples, he adds, "All seem to vary immediately on attaining new ground, assuming many aspects in different districts."Unquestionably these statements support, in a very absolute manner, Mr. Wallace's opinion, while making directly against my own. It is but fair, however, to add that the cases are not numerous (some half-dozen at the most, and all within the limits of a single genus), and that, even in the opinion of my informant himself, the facts have not hitherto been sufficiently investigated for any decisive judgement to be formed upon them.
[57]Since the above was written, I have heard of some cases which seem to present greater difficulties to our theory than those above quoted. These refer to some of the numerous species of land mollusca which inhabit the isolated rocks near Madeira (Dezertas). My informant is Dr. Grabham, who has himself investigated the matter, and reports as follows:—
"It is no uncommon thing to meet with examples of the same species, sub-fossil, recent, and living upon one spot, and presenting no variation in the long record of descent." Then, after naming these examples, he adds, "All seem to vary immediately on attaining new ground, assuming many aspects in different districts."
Unquestionably these statements support, in a very absolute manner, Mr. Wallace's opinion, while making directly against my own. It is but fair, however, to add that the cases are not numerous (some half-dozen at the most, and all within the limits of a single genus), and that, even in the opinion of my informant himself, the facts have not hitherto been sufficiently investigated for any decisive judgement to be formed upon them.
[58]Vol. xliii. p. 127.
[58]Vol. xliii. p. 127.
[59]This refers to what I understand Mr. Wallace to say in theNaturecorrespondence is the supposition on which his own theory of the origin of species by cross-infertility is founded. But in the original statement of that theory itself, it is everywhere "supposed" that when species are originated by cross-infertility, theinitialchangeisthe physiological change. In his original statement of that theory, therefore, he literally went further than I had gone in my "original paper," with reference to supposing the physiological change to be the initial change. I do not doubt that this is due to some oversight of expression; but it is curious that, having made it, he should still continue his endeavour to fix exactly the same oversight upon me.
[59]This refers to what I understand Mr. Wallace to say in theNaturecorrespondence is the supposition on which his own theory of the origin of species by cross-infertility is founded. But in the original statement of that theory itself, it is everywhere "supposed" that when species are originated by cross-infertility, theinitialchangeisthe physiological change. In his original statement of that theory, therefore, he literally went further than I had gone in my "original paper," with reference to supposing the physiological change to be the initial change. I do not doubt that this is due to some oversight of expression; but it is curious that, having made it, he should still continue his endeavour to fix exactly the same oversight upon me.
[60]"Positive segregation" is Mr. Gulick's term for forms of homogamy other than that which is due to selective fertility. Of these other, or "positive" forms, natural selection is one; but as it is far from being theonlyone, the criticism points out that utility is not theonlyconserving principle with which selective fertility may be associated.
[60]"Positive segregation" is Mr. Gulick's term for forms of homogamy other than that which is due to selective fertility. Of these other, or "positive" forms, natural selection is one; but as it is far from being theonlyone, the criticism points out that utility is not theonlyconserving principle with which selective fertility may be associated.
[61]By Intensive Segregation Mr. Gulick means what I have called Independent Variability.
[61]By Intensive Segregation Mr. Gulick means what I have called Independent Variability.
[62]His sentence, "all fertility not correlated with someusefulvariation has a constant tendency to effect its own elimination," still further restricts the possible action of physiological selection to cases where at least one of the other forms of homogamy with which it is associated is natural selection. Or, in other words, it is represented that physiological selection must always be associated with natural selection, even if it be likewise associated with any other form of exclusive breeding. But as this further limitation appears to me self-evidently unjustifiable (seeing that utility is not the only possible means of securing effective isolation) I here neglect it, and take the wider ground marked out above. It is needless to say that this is giving Mr. Wallace every possible advantage, by not holding him to his still narrower ground.
[62]His sentence, "all fertility not correlated with someusefulvariation has a constant tendency to effect its own elimination," still further restricts the possible action of physiological selection to cases where at least one of the other forms of homogamy with which it is associated is natural selection. Or, in other words, it is represented that physiological selection must always be associated with natural selection, even if it be likewise associated with any other form of exclusive breeding. But as this further limitation appears to me self-evidently unjustifiable (seeing that utility is not the only possible means of securing effective isolation) I here neglect it, and take the wider ground marked out above. It is needless to say that this is giving Mr. Wallace every possible advantage, by not holding him to his still narrower ground.
[63]In ourNaturecorrespondence of 1890-1891, Mr. Wallace remarked: "If Dr. Romanes will carefully work out numerically (as I have attempted to do) a few cases showing the preservative and accumulative agency of pure physiological selection within an otherwise undifferentiated species, he will do more for his theory than volumes of general disquisition or any number of assertions that itdoespossess this power." Several months before this was written I had already in my hands Mr. Moulton's letter, with its accompanying calculations.
[63]In ourNaturecorrespondence of 1890-1891, Mr. Wallace remarked: "If Dr. Romanes will carefully work out numerically (as I have attempted to do) a few cases showing the preservative and accumulative agency of pure physiological selection within an otherwise undifferentiated species, he will do more for his theory than volumes of general disquisition or any number of assertions that itdoespossess this power." Several months before this was written I had already in my hands Mr. Moulton's letter, with its accompanying calculations.
[64]As, for example, in the case of sexuality in general. It is not to the advantage of such individual male Arthropoda as perish after the performance of the sexual act that they should perform it; but its performance is necessary for the perpetuation of their species.—G. J. R.
[64]As, for example, in the case of sexuality in general. It is not to the advantage of such individual male Arthropoda as perish after the performance of the sexual act that they should perform it; but its performance is necessary for the perpetuation of their species.—G. J. R.
[65]In this anticipation Mr. Moulton is right. The well-known botanist, Mr. Bennett, read a most interesting paper on the subject before the British Association in 1881. His results have since been corroborated by other observers. In particular, Mr. R. M. Christy has recorded the movements of 76 insects while visiting at least 2,400 flowers. (Entomologist, July 1883, andZool. Journal Lin. Soc., August 1883.) The following is an analysis of his results. In the case of butterflies, in twelve observations on nearly as many species, there are recorded altogether 99 visits to fifteen species of flowers; and of these 99 visits 94 were constant to the same species, leaving only 5 visits to any other, or second species. In the case of the hive-bee, there were 8 individuals observed: these visited altogether 258 flowers, and all the visits paid by the same individual were paid to the same species in each of the eight cases. Lastly, as regards bumble-bees, there were altogether observed 55 individuals belonging to four species. These paid altogether 1751 visits to 94 species of flowers. Of these 1751 visits, 1605 were paid to one species, 131 to two species, 16 to three, 6 to four, and 1 to five. Adding all these results together, we find that 75 insects (butterflies and bees) visited 117 species of flowers: of these visits, 1957 were constant to one species of flower; 136 were paid also to a second species, 16 also to a third, 6 also to a fourth, and 1 also to a fifth. Or, otherwise stated, while 1957 were absolutely constant, from such absolute constancy there were only 159 deviations. Moreover, if we eliminate three individual humble bees, which paid nearly an equal number of visits to two species (and, therefore, would have ministered to the work of physiological selection almost as well as the others), the 159 deviations become reduced to 72, or about four per cent. of the whole.—G. J. R.
[65]In this anticipation Mr. Moulton is right. The well-known botanist, Mr. Bennett, read a most interesting paper on the subject before the British Association in 1881. His results have since been corroborated by other observers. In particular, Mr. R. M. Christy has recorded the movements of 76 insects while visiting at least 2,400 flowers. (Entomologist, July 1883, andZool. Journal Lin. Soc., August 1883.) The following is an analysis of his results. In the case of butterflies, in twelve observations on nearly as many species, there are recorded altogether 99 visits to fifteen species of flowers; and of these 99 visits 94 were constant to the same species, leaving only 5 visits to any other, or second species. In the case of the hive-bee, there were 8 individuals observed: these visited altogether 258 flowers, and all the visits paid by the same individual were paid to the same species in each of the eight cases. Lastly, as regards bumble-bees, there were altogether observed 55 individuals belonging to four species. These paid altogether 1751 visits to 94 species of flowers. Of these 1751 visits, 1605 were paid to one species, 131 to two species, 16 to three, 6 to four, and 1 to five. Adding all these results together, we find that 75 insects (butterflies and bees) visited 117 species of flowers: of these visits, 1957 were constant to one species of flower; 136 were paid also to a second species, 16 also to a third, 6 also to a fourth, and 1 also to a fifth. Or, otherwise stated, while 1957 were absolutely constant, from such absolute constancy there were only 159 deviations. Moreover, if we eliminate three individual humble bees, which paid nearly an equal number of visits to two species (and, therefore, would have ministered to the work of physiological selection almost as well as the others), the 159 deviations become reduced to 72, or about four per cent. of the whole.—G. J. R.
[66]Here follows the Appendix presenting the calculations on which the above results are founded; but it seems unnecessary to reproduce it on the present occasion.—G. J. R.
[66]Here follows the Appendix presenting the calculations on which the above results are founded; but it seems unnecessary to reproduce it on the present occasion.—G. J. R.
[67]Doctrine of Descent and Darwinism, Eng. trans. p. 139.
[67]Doctrine of Descent and Darwinism, Eng. trans. p. 139.
Transcriber's NotesIn paragraph 4 of page 171 "peculiarites" has been corrected to "peculiarities"Variable spacing in the following abbreviation was left as it was in the original: "i. e." (22 instances) and "i.e." (14 instances).Different hyphenation patterns were left as in the original text:prepotent (1 instance)pre-potent (1 instance)presupposes (1)pre-supposes (1)reacting(5)re-acting (1)restatement (1)re-statement (2)superinduced (2)super-induced (1)
In paragraph 4 of page 171 "peculiarites" has been corrected to "peculiarities"
Variable spacing in the following abbreviation was left as it was in the original: "i. e." (22 instances) and "i.e." (14 instances).
Different hyphenation patterns were left as in the original text:
prepotent (1 instance)pre-potent (1 instance)presupposes (1)pre-supposes (1)reacting(5)re-acting (1)restatement (1)re-statement (2)superinduced (2)super-induced (1)