I
know.

{268} <Note in original.> History of pigeons shows increase of
peculiarities during last years.

{269} Compare an obscure passage in the Essay of 1842, p. 14.

{270} <Note in original.> Certainly <two pages in the MS.> ought to
be here introduced, viz., difficulty in forming such organ, as eye,
by selection. <In the _Origin_, Ed. i., a chapter on _Difficulties
on Theory_ follows that on _Laws of Variation_, and precedes that
on _Instinct_: this was also the arrangement in the Essay of 1842;
whereas in the present Essay _Instinct_ follows _Variation_ and
precedes _Difficulties_.>

CHAPTER III

ON THE VARIATION OF INSTINCTS AND OTHER MENTAL ATTRIBUTES UNDER
DOMESTICATION AND IN STATE OF NATURE; ON THE DIFFICULTIES IN THIS
SUBJECT; AND ON ANALOGOUS DIFFICULTIES WITH RESPECT TO CORPOREAL
STRUCTURES

_Variation of mental attributes under domestication._

I have as yet only alluded to the mental qualities which differ greatly
in different species. Let me here premise that, as will be seen in the
Second Part, there is no evidence and consequently no attempt to show
that _all_ existing organisms have descended from any one common
parent-stock, but that only those have so descended which, in the
language of naturalists, are clearly related to each other. Hence the
facts and reasoning advanced in this chapter do not apply to the first
origin of the senses{271}, or of the chief mental attributes, such as of
memory, attention, reasoning, &c., &c., by which most or all of the
great related groups are characterised, any more than they apply to the
first origin of life, or growth, or the power of reproduction. The
application of such facts as I have collected is merely to the
differences of the primary mental qualities and of the instincts in the
species{272} of the several great groups. In domestic animals every
observer has remarked in how great a degree, in the individuals of the
same species, the dispositions, namely courage, pertinacity, suspicion,
restlessness, confidence, temper, pugnaciousness, affection, care of
their young, sagacity, &c., &c., vary. It would require a most able
metaphysician to explain how many primary qualities of the mind must be
changed to cause these diversities of complex dispositions. From these
dispositions being inherited, of which the testimony is unanimous,
families and breeds arise, varying in these respects. I may in