This paper contained the sentence so often quoted since, "A physical fact is as sacred as a moral principle. Our own nature demands from us this double allegiance." This expressed the secret of his whole life. Every fact in nature was sacred to him, as part of an intellectual conception expressed in the history of the earth and the beings living upon it.
On the 2nd of December, he was called to a meeting of the Ma.s.sachusetts Board of Agriculture at Fitchburg, where he lectured in the evening on "The structural growth of domesticated animals."
Those who accompanied him, and knew the mental and physical depression which had hung about him for weeks, could not see him take his place on the platform, without anxiety. And yet, when he turned to the blackboard, and, with a single sweep of the chalk, drew the faultless outline of an egg, it seemed impossible that anything could be amiss with the hand or the brain that were so steady and so clear.
The end, nevertheless, was very near. Although he dined with friends the next day, and was present at a family festival that week, he spoke of a dimness of sight, and of feeling "strangely asleep." On the 6th he returned early from the Museum, complaining of great weariness, and from that time he never left his room.
Attended in his illness by his friends, Dr. Brown-Sequard and Dr.
Morrill Wyman, and surrounded by his family, the closing week of his life was undisturbed by acute suffering and full of domestic happiness. Even the voices of his brother and sisters were not wholly silent, for the wires that thrill with so many human interests brought their message of greeting and farewell across the ocean to his bedside. The thoughts and aims for which he had lived were often on his lips, but the affections were more vivid than the intellect in these last hours. The end came very peacefully, on the 14th of December, 1873. He lies buried at Mount Auburn. The boulder that makes his monument came from the glacier of the Aar, not far from the spot where his hut once stood; and the pine-trees which are fast growing up to shelter it were sent by loving hands from his old home in Switzerland. The land of his birth and the land of his adoption are united in his grave.