That you and I have fundamentally different political principles must, I think, have become obvious to both of us during the progress of the American War. The fact is made still more plain by your printed letter, the tone and spirit of which I greatly admired without being able to recognise in it any important fact or argument which had not passed through my mind before I joined the Jamaica Committee. Thus there is nothing for it but for us to agree to differ, each supporting his own side to the best of his ability, and respecting his friend's freedom as he would his own, and doing his best to remove all petty bitterness from that which is at bottom one of the most important constitutional battles in which Englishmen have for many years been engaged. If you and I are strong enough and wise enough, we shall be able to do this, and yet preserve that love for one another which I value as one of the good things of my life. If not, we shall come to grief. I mean to do my best. Ever yours faithfully, T.H. Huxley. [Huxley was always of opinion that to write a good elementary text-book required a most extensive and intimate knowledge of the subject under discussion. Certainly the "Lessons on Elementary Physiology" which appeared at the end of 1866 were the outcome of such knowledge, and met with a wonderful and lasting success as a text-book. A graceful compliment was passed upon it by Sir William Lawrence, when, in thanking the author for the gift of the book, he wrote (January 24, 1867), "in your modest book 'indocti discant, ament meminisse periti!'" This was before the days of American copyright, and English books were usually regarded as fair prey by the mass of American publishers. Among the exceptions to this practical rule were the firm of D. Appleton & Co., who made it a point of honour to treat foreign authors as though they were legally entitled to some equitable rights. On their behalf an arrangement was made for an authorised American edition of the "Physiology" by Dr. Youmans, whose acquaintance thus made my father did not allow to drop. It is worth noting that by the year 1898 this little book had passed through four editions, and been reprinted thirty-one times.] CHAPTER 1.21. 1867. [It has already been noted that Huxley's ethnological work continued this year with a second series of lectures at the Royal Institution, while he enlarged his paper on "Two widely contrasted forms of Human Crania," and published it in the "Journal of Anatomy." One paleontological memoir of his appeared this year on Acanthopholis, a fossil from the chalk marl, an additional piece of work for which he excuses himself to Sir Charles Lyell (January 4, 1867):--] The new reptile advertised in "Geol. Mag." has turned up in the way of business, and I could not help giving a notice of it, or I should not have undertaken anything fresh just now.