. . .When one has been so long separated, even accidentally, from a friend as I have been from you, my dear Agassiz, it is difficult to find beginning or end to a letter. The kindly remembrance which you send me is evidence that my long silence has not seemed strange to you. . .It would be wasting words to tell you how I have been prevented, by the distractions of my life, always increasing with old age, from acknowledging the admirable things received from you, --upon living and fossil fishes, echinoderms, and glaciers. My admiration of your boundless activity, of your beautiful intellectual life, increases with every year. This admiration for your work and your bold excursions is based upon the most careful reading of all the views and investigations, for which I have to thank you. This very week I have read with great satisfaction your truly philosophical address, and your long treatise in Cotta's fourth "Jahresschrift." Even L. von Buch confessed that the first half of your treatise, the living presentation of the succession of organized beings, was full of truth, sagacity, and novelty. I in no way reproach you, my dear friend, for the urgent desire expressed in all your letters, that your oldest friends should accept your comprehensive geological view of your ice-period. It is very noble and natural to wish that what has impressed us as true should also be recognized by those we love. . .I believe I have read and compared all that has been written for and against the ice-period, and also upon the transportation of boulders, whether pushed along or carried by floods or gliding over slopes. My own opinion, as you know, can have no weight or authority, since I have not myself seen the most decisive points. Indeed I am, perhaps wrongly, inclined to look upon all geological theories as having their being in a mythical region, in which, with the progress of physics, the phantasms are modified century by century. But the "elephants caught in the ice," and Cuvier's "instantaneous change of climate," seem to me no more intelligible today than when I wrote my Asiatic fragments. According to all that we know of the decrease of heat in the earth, I cannot understand such a change of temperature in a space of time which does not also allow for the decaying of flesh. I understand much better how wolves, hares, and dogs, should they fall to-day into clefts of the frozen regions of Northern Siberia (and the so-called "elephant-ice" is in plain prose only porphyritic drift mixed with ice-crystals, true drift material), might retain their flesh and muscles. . .But I am only a grumbling rebellious subject in your kingdom. . .Do not be vexed with a friend who is more than ever impressed with your services to geology, your philosophical views of nature, your profound knowledge of organized beings. . . With old attachment and the warmest friendship, your A. DE HUMBOLDT.