But since he did not mean to marry for the next five years⁠—his more pressing business was to look into Louis’ new book on fever, which he was specially interested in, because he had known Louis in Paris, and had followed many anatomical demonstrations in order to ascertain the specific differences of typhus and typhoid. He went home and read far into the smallest hour, bringing a much more testing vision of details and relations into this pathological study than he had ever thought it necessary to apply to the complexities of love and marriage, these being subjects on which he felt himself amply informed by literature, and that traditional wisdom which is handed down in the genial conversation of men. Whereas fever had obscure conditions, and gave him that delightful labor of the imagination which is not mere arbitrariness, but the exercise of disciplined power⁠—combining and constructing with the clearest eye for probabilities and the fullest obedience to knowledge; and then, in yet more energetic alliance with impartial Nature, standing aloof to invent tests by which to try its own work.