A certain measure of plasticity has to be counted in as part of their very nature.

Even in the bee, with its highly definite instincts, there is a certain flexibility bound up with each of these; so that, for instance, the inborn faculty of building up the comb regularly is modified if the hive happens to be of an awkward shape.

Yet, as compared with what remains over, the characters that we are able to distinguish as racial must show fixity.
Unfortunately, habits show fixity too.

Yet habits belong to the plastic side of our nature; for, in forming a habit, we are plastic at the start, though hardly so once we have let ourselves go.

Habits, then, must be discounted in our search for the hereditary bias in our lives.
It is no use trying to disguise the difficulties attending an inquiry into race.
* * * * * These difficulties notwithstanding, in the rest of this chapter let us consider a few of what are usually taken to be racial features of man.