Gentle and lovable as she was in every other aspect, towards Sebastian she seemed like a lynx-eyed detective.  She had some object in view, I thought, almost as abstract as his own—­some object to which, as I judged, she was devoting her life quite as single-mindedly as Sebastian himself had devoted his to the advancement of science.

“Why did she become a nurse at all?” I asked once of her friend, Mrs. Mallet.  “She has plenty of money, and seems well enough off to live without working.”

“Oh, dear, yes,” Mrs. Mallet answered.  “She is independent, quite; has a tidy little income of her own—­six or seven hundred a year—­ and she could choose her own society.  But she went in for this mission fad early; she didn’t intend to marry, she said; so she would like to have some work to do in life.  Girls suffer like that, nowadays.  In her case, the malady took the form of nursing.”

“As a rule,” I ventured to interpose, “when a pretty girl says she doesn’t intend to marry, her remark is premature.  It only means—­”

“Oh, yes, I know.  Every girl says it; ’tis a stock property in the popular masque of Maiden Modesty.  But with Hilda it is different.  And the difference is—­that Hilda means it!”

“You are right,” I answered.  “I believe she means it.  Yet I know one man at least—­” for I admired her immensely.

Mrs. Mallet shook her head and smiled.  “It is no use, Dr. Cumberledge,” she answered.  “Hilda will never marry.  Never, that is to say, till she has attained some mysterious object she seems to have in view, about which she never speaks to anyone—­not even to me.  But I have somehow guessed it!”

“And it is?”

“Oh, I have not guessed what it is:  I am no Oedipus.  I have merely guessed that it exists.  But whatever it may be, Hilda’s life is bounded by it.  She became a nurse to carry it out, I feel confident.  From the very beginning, I gather, a part of her scheme was to go to St. Nathaniel’s.  She was always bothering us to give her introductions to Dr. Sebastian; and when she met you at my brother Hugo’s, it was a preconcerted arrangement; she asked to sit next you, and meant to induce you to use your influence on her behalf with the Professor.  She was dying to get there.”

“It is very odd,” I mused.  “But there!—­women are inexplicable!”

“And Hilda is in that matter the very quintessence of woman.  Even I, who have known her for years, don’t pretend to understand her.”

A few months later, Sebastian began his great researches on his new anaesthetic.  It was a wonderful set of researches.  It promised so well.  All Nat’s (as we familiarly and affectionately styled St. Nathaniel’s) was in a fever of excitement over the drug for a twelvemonth.