Much stress is laid on the persistence of moral impressions made in childhood, and the conclusion is drawn, that the effects of early teaching must be important in a corresponding degree.  I acknowledge the fact, so far as has been explained in the chapter on Early Sentiments, but there is a considerable set-off on the other side.  Those teachings that conform to the natural aptitudes of the child leave much more enduring marks than others.  Now both the teachings and the natural aptitudes of the child are usually derived from its parents.  They are able to understand the ways of one another more intimately than is possible to persons not of the same blood, and the child instinctively assimilates the habits and ways of thought of its parents.  Its disposition is “educated” by them, in the true sense of the word; that is to say, it is evoked, not formed by them.  On these grounds I ascribe the persistence of many habits that date from early home education, to the peculiarities of the instructors rather than to the period when the instruction was given.  The marks left on the memory by the instructions of a foster-mother are soon sponged clean away.  Consider the history of the cuckoo, which is reared exclusively by foster-mothers.  It is probable that nearly every young cuckoo, during a series of many hundred generations, has been brought up in a family whose language is a chirp and a twitter.  But the cuckoo cannot or will not adopt that language, or any other of the habits of its foster-parents.  It leaves its birthplace as soon as it is able, and finds out its own kith and kin, and identifies itself henceforth with them.  So utterly are its earliest instructions in an alien bird-language neglected, and so completely is its new education successful, that the note of the cuckoo tribe is singularly correct.

DOMESTICATION OF ANIMALS.[14]

  [Footnote 14:  This memoir is reprinted from the Transactions of
  the Ethnological Society]

Before leaving the subject of Nature and Nurture, I would direct attention to evidence bearing on the conditions under which animals appear first to have been domesticated.  It clearly shows the small power of nurture against adverse natural tendencies.

The few animals that we now possess in a state of domestication were first reclaimed from wildness in prehistoric times.  Our remote barbarian ancestors must be credited with having accomplished a very remarkable feat, which no subsequent generation has rivalled.  The utmost that we of modern times have succeeded in doing, is to improve the races of those animals that we received from our forefathers in an already domesticated condition.