The Builders by Ellen Glasgow

For the rest of the afternoon she carried the letter hidden in her uniform, where, from time to time, she could pause in her task, and put her hand reassuringly on the edge of the envelope. Not until evening, when she had left her patient and was back in her room, did she unfold the pages, and begin slowly to read what he had written. The first sentences, as she had expected, were stiff and constrained -- she had known that until he could speak freely he would speak no word of love to her -- but, as soon as he had passed from the note of feeling to the discussion of impersonal issues, he wrote as earnestly and spontaneously as he had talked to Sloane on that October afternoon at Briarlay. Another woman, she realized, might have been disappointed; but the ironic past had taught her that emotion, far from being the only bond with a man like Blackburn, was perhaps the least enduring of the ties that held them together.

His love, if it ever came to her, would be the flower, not of transient passion, but of the profound intellectual sympathy which had first drawn their minds, not their hearts, to each other. Both had passed through the earlier fires of racial impulse; both had been scorched, not warmed by the flames; and both had learned that the only permanent love is the love that is rooted as deeply in thought as in desire.