I think you would do well to publish for a while more text than plates. You could do this the better because your text is excellent, full of new and important ideas, expressed with admirable clearness. The charming letter (again without a date) which preceded your package impressed me painfully. I see you are ill again; you complain of congestion of the head and eyes. For mercy's sake take care of your health which is so dear to us. I am afraid you work too much, and (shall I say it frankly?) that you spread your intellect over too many subjects at once. I think that you should concentrate your moral and also your pecuniary strength upon this beautiful work on fossil fishes. In so doing you will render a greater service to positive geology, than by these general considerations (a little icy withal) on the revolutions of the primitive world; considerations which, as you well know, convince only those who give them birth. In accepting considerable sums from England, you have, so to speak, contracted obligations to be met only by completing a work which will be at once a monument to your own glory and a landmark in the history of science. Admirable and exact as your researches on other fossils are, your contemporaries claim from you the fishes above all. You will say that this is making you the slave of others; perfectly true, but such is the pleasing position of affairs here below. Have I not been driven for thirty-three years to busy myself with that tiresome America, and am I not, even yet, daily insulted because, after publishing thirty-two volumes of the great edition in folio and in quarto, and twelve hundred plates, one volume of the historical section is wanting? We men of letters are the servants of an arbitrary master, whom we have imprudently chosen, who flatters and pets us first, and then tyrannizes over us if we do not work to his liking. You see, my dear friend, I play the grumbling old man, and, at the risk of deeply displeasing you, place myself on the side of the despotic public. . .