¹ Mr. Kerns, to whom I submitted the draft of these Notes, writes me that he would re-phrase the passage on page 43 to read: ‘It seems that both Gray and Hirt, whose views are in all essential respects so divergent, are bold in the extent’, etc. This statement removes all possible ambiguity. I have, however, let my declaration of principle stand in order that my personal position may be perfectly clear.