allied species, see Origin, Ed. i. p. 257, vi. p. 377. In the present essay the author does not distinguish between fertility between species and the fertility of the hybrid offspring, a point on which he insists in the Origin, Ed. i. p. 245, vi. p. 365.
68
Ackermann (Ber. d. Vereins f. Naturkunde zu Kassel, 1898, p. 23) quotes from Gloger that a cross has been effected between a domestic hen and a Tetrao tetrix; the offspring died when three days old.
69
No doubt the sexual cells are meant. I do not know on what evidence it is stated that the mule has bred.
70
The sentence is all but illegible. I think that the author refers to forms usually ranked as varieties having been marked as species when it was found that they were sterile together. See the case of the red and blue Anagallis given from Gärtner in the Origin, Ed. i. p. 247, vi. p. 368.
71
In the Origin, Ed. i. p. 258, where the author speaks of constitutional differences in this connexion, he specifies that they are confined to the reproductive system.
72
The sensitiveness of the reproductive system to changed conditions is insisted on in the Origin, Ed. i. p. 8, vi. p. 10.
The ferret is mentioned, as being prolific in captivity, in Var. under Dom., Ed. 2, ii. p. 90.
73
Lindley’s remark is quoted in the Origin, Ed. i. p. 9. Linnæus’ remark is to the effect that Alpine plants tend to be sterile under cultivation (see Var. under Dom., Ed. 2, ii. p. 147). In the same place the author speaks of peat-loving plants being sterile in our gardens, – no doubt the American bog-plants referred to above. On the following page (p. 148) the sterility of the lilac (Syringa persica and chinensis) is referred to.
74
The author probably means that the increase in the petals is due to a greater food supply being available for them owing to sterility. See the discussion in Var. under Dom., Ed. 2, ii. p. 151. It must be noted that doubleness of the flower may exist without noticeable sterility.
75
I have not come across this case in the author’s works.
76
For the somewhat doubtful case of the cheetah (Felis jubata) see Var. under Dom., Ed. 2, ii. p. 133. I do not know to what fact “pig in India” refers.
77
This sentence should run “on which depends their incapacity to breed in unnatural conditions.”
78
This sentence ends in confusion: it should clearly close with the words “refused to breed” in place of the bracket and the present concluding phrase.
79
The author doubtless refers to the change produced by the summation of variation by means of selection.
80
The meaning of this sentence is made clear by a passage in the MS. of 1844: – “Until man selects two varieties from the same stock, adapted to two climates or to other different external conditions, and confines each rigidly for one or several thousand years to such conditions, always selecting the individuals best adapted to them, he cannot be said to have even commenced the experiment.” That is, the attempt to produce mutually sterile domestic breeds.
81
This passage is to some extent a repetition of a previous one and may have been intended to replace an earlier sentence. I have thought it best to give both. In the Origin, Ed. i. p. 141, vi. p. 176, the author gives his opinion that the power of resisting diverse conditions, seen in man and his domestic animals, is an example “of a very common flexibility of constitution.”
82
In the Origin, Ed. i. Chs. I. and V., the author does not admit reproduction, apart from environment, as being a cause of variation. With regard to the cumulative effect of new conditions there are many passages in the Origin, Ed. i. e.g. pp. 7, 12, vi. pp. 8, 14.
83
As already pointed out, this is the important principle investigated in the author’s Cross and Self-Fertilisation. Professor Bateson has suggested to me that the experiments should be repeated with gametically pure individuals.
84
In the Origin a chapter is given up to “difficulties on theory”: the discussion in the present essay seems slight even when it is remembered how small a space is here available. For Tibia &c. see p. 48.
85
This may be interpreted “The general structure of a bat is the same as that of non-flying mammals.”
86
That is truly winged fish.
87
The terrestrial woodpecker of S. America formed the subject of a paper by Darwin, Proc. Zool. Soc., 1870. See Life and Letters, vol. iii. p. 153.
88
The same proviso occurs in the Origin, Ed. i. p. 207, vi. p. 319.
89
The tameness of the birds in the Galapagos is described in the Journal of Researches (1860), p. 398. Dogs and rabbits are probably mentioned as cases in which the hereditary fear of man has been lost. In the 1844 MS. the author states that the Cuban feral dog shows great natural wildness, even when caught quite young.
90
In the Origin, Ed. i. p. 207, vi. p. 319, he refuses to define instinct. For Lord Brougham’s definition see his Dissertations on Subjects of Science etc., 1839, p. 27.
91
See James Hogg (the Ettrick Shepherd), Works, 1865, Tales and Sketches, p. 403.
92
This refers to the tailor-bird making use of manufactured thread supplied to it, instead of thread twisted by itself.
93
Often lost applies to instinct: birds get wilder is printed in a parenthesis because it was apparently added as an after-thought. Nest without roof refers to the water-ousel omitting to vault its nest when building in a protected situation.
94
In the MS. of 1844 is an interesting discussion on faculty as distinct from instinct.
95
At this date and for long afterwards the inheritance of acquired characters was assumed to occur.
96
Part II. is here intended: see the Introduction.
97
The meaning is that the attitude assumed in shamming is not accurately like that of death.
98
This refers to the transandantes sheep mentioned in the MS. of 1844, as having acquired a migratory instinct.
99
In the Origin, Ed. i. p. 209, vi. p. 321, Mozart’s pseudo-instinctive skill in piano-playing is mentioned. See Phil. Trans., 1770, p. 54.
100
In the discussion on bees’ cells, Origin, Ed. i. p. 225, vi. p. 343, the author acknowledges that his theory originated in Waterhouse’s observations.
101
The hawfinch-and Sylvia-types are figured in the Journal of Researches, p. 379. The discussion of change of form in relation to change of instinct is not clear, and I find it impossible to suggest a paraphrase.
102
I should interpret this obscure sentence as follows, “No such opposing law is known, but in all works on the subject a law is (in flat contradiction to all known facts) assumed to limit the possible amount of variation.” In the Origin, the author never limits the power of variation, as far as I know.
