Note 63 — APPENDIX B. An Examination by Mr. Fletcher Moulton of Mr. Wallace's Calculation touching the Possibility Of Physiological Selection ever acting alone.

In our Nature correspondence of 1890-1891, Mr. Wallace remarked: "If Dr. Romanes will carefully work out numerically (as I have attempted to do) a few cases showing the preservative and accumulative agency of pure physiological selection within an otherwise undifferentiated species, he will do more for his theory than volumes of general disquisition or any number of assertions that it does possess this power." Several months before this was written I had already in my hands Mr. Moulton's letter, with its accompanying calculations.