Note 8 — LECTURE XXII

Since this was written for the first edition observations of this process have been considerably increased, and discussions as to the exact interpretation of these are in full tide; we are surrounded by a wealth of new observations, facts, and explanations, without having attained to a consistent and unified theory. Several naturalists, such as Boveri, Häcker, Wilson, and others, have attempted interpretations, but these are in many points contradictory to one another. It is therefore impossible to enter into the question in detail here; further light from new observations must be awaited. So much we may say, however, that it is not chance alone which presides over the re-arrangement of the chromosomes during the reducing divisions; affinities play a part also; there are stronger or weaker attractions between the chromosomes, which aid in determining their relative position to one another.