[{212}] «Note in the original.» “It appears that slight changes of condition «are» good for health; that more change affects the generative system, so that variation results in the offspring; that still more change checks or destroys fertility not of the offspring.” Compare the Origin, Ed. i. p. 9, vi. p. 11. What the meaning of “not of the offspring” may be is not clear.
[{213}] In the Origin, Ed. i. p. 41, vi. p. 46 the question is differently treated; it is pointed out that a large stock of individuals gives a better chance of available variations occurring. Darwin quotes from Marshall that sheep in small lots can never be improved. This comes from Marshall’s Review of the Reports to the Board of Agriculture, 1808, p. 406. In this Essay the name Marshall occurs in the margin. Probably this refers to loc. cit. p. 200, where unshepherded sheep in many parts of England are said to be similar owing to mixed breeding not being avoided.
[{214}] See Origin, Ed. i. p. 8, vi. p. 8.
[{215}] See Origin, Ed. i. p. 42, vi. p. 48.
[{216}] «Note in the original.» There are white peacocks.
[{217}] «Note in the original.» There are varieties of asparagus.
[{218}] In Chapter II of the first edition of the Origin Darwin insists rather on the presence of variability in a state of nature; see, for instance, p. 45, Ed. vi. p. 53, “I am convinced that the most experienced naturalist would be surprised at the number of the cases of variability ... which he could collect on good authority, as I have collected, during a course of years.”
[{219}] See Origin, Ed. i. p. 44, vi. p. 52.
[{220}] «Note in the original.» Here discuss what is a species, sterility can most rarely be told when crossed.—Descent from common stock.
[{221}] «Note in the original.» Give only rule: chain of intermediate forms, and analogy; this important. Every Naturalist at first when he gets hold of new variable type is quite puzzled to know what to think species and what variations.