“ A man's mental reactions with the atmosphere of life must go on, whether he will or no, as between his blood and the air he breathes. ”
 Oliver Wendell Holmes Sr., The Professor at the Breakfast-Table (1860). copy citation

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“finding nothing too small for his contemplation in the markings of the grammatophora subtilissima, and nothing too large in the movement of the solar system towards the star Lambda of the constellation Hercules;—and the question is, whether there is anything left for me, the Professor, to suck out of creation, after my lively friend has had his straw in the bung-hole of the Universe! A man's mental reactions with the atmosphere of life must go on, whether he will or no, as between his blood and the air he breathes. As to catching the residuum of the process, or what we call thought,—the gaseous ashes of burned-out thinking,—the excretion of mental respiration,—that will depend on many things, as, on having a favorable intellectual temperature about one, and a fitting receptacle.—I sow more thought-seeds in twenty-four hours' travel over the desert-sand along which my lonely consciousness paces day and night, than I shall throw into soil where it will germinate, in a year.” source