She looked me through searchingly.  “I will not destroy your illusion,” she answered, after a pause.  “It is a noble and generous one.  But is it not largely based on an ascetic face, long white hair, and a moustache that hides the cruel corners of the mouth?  For the corners are cruel.  Some day, I will show you them.  Cut off the long hair, shave the grizzled moustache—­and what then will remain?” She drew a profile hastily.  “Just that,” and she showed it me.  ’Twas a face like Robespierre’s, grown harder and older and lined with observation.  I recognised that it was in fact the essence of Sebastian.

Next day, as it turned out, the Professor himself insisted upon testing lethodyne in his own person.  All Nat’s strove to dissuade him.  “Your life is so precious, sir—­the advancement of science!” But the Professor was adamantine.

“Science can only be advanced if men of science will take their lives in their hands,” he answered, sternly.  “Besides, Nurse Wade has tried.  Am I to lag behind a woman in my devotion to the cause of physiological knowledge?”

“Let him try,” Hilda Wade murmured to me.  “He is quite right.  It will not hurt him.  I have told him already he has just the proper temperament to stand the drug.  Such people are rare:  He is one of them.”

We administered the dose, trembling.  Sebastian took it like a man, and dropped off instantly, for lethodyne is at least as instantaneous in its operation as nitrous oxide.

He lay long asleep.  Hilda and I watched him.

After he had lain for some minutes senseless, like a log, on the couch where we had placed him, Hilda stooped over him quietly and lifted up the ends of the grizzled moustache.  Then she pointed one accusing finger at his lips.  “I told you so,” she murmured, with a note of demonstration.

“There is certainly something rather stern, or even ruthless, about the set of the face and the firm ending of the lips,” I admitted, reluctantly.

“That is why God gave men moustaches,” she mused, in a low voice; “to hide the cruel corners of their mouths.”

“Not always cruel,” I cried.

“Sometimes cruel, sometimes cunning, sometimes sensuous; but nine times out of ten best masked by moustaches.”

“You have a bad opinion of our sex!” I exclaimed.

“Providence knew best,” she answered.  “It gave you moustaches.  That was in order that we women might be spared from always seeing you as you are.  Besides, I said ‘Nine times out of ten.’  There are exceptions—­such exceptions!”

On second thought, I did not feel sure that I could quarrel with her estimate.