, we know of old the purity and vigour of your
circulating fluid. You shall have the honour of advancing science once
more. Hold up your finger."

Hilda held up her forefinger unhesitatingly. She was used to such
requests; and, indeed, Sebastian had acquired by long experience the
faculty of pinching the finger-tip so hard, and pressing the point of a
needle so dexterously into a minor vessel, that he could draw at once a
small drop of blood without the subject even feeling it.

The Professor nipped the last joint between his finger and thumb for a
moment till it was black at the end; then he turned to the saucer at his
side, which Hilda herself had placed there, and chose from it, cat-like,
with great deliberation and selective care, a particular needle. Hilda's
eyes followed his every movement as closely and as fearlessly as
ever. Sebastian's hand was raised, and he was just about to pierce the
delicate white skin, when, with a sudden, quick scream of terror, she
snatched her hand away hastily.

The Professor let the needle drop in his astonishment. "What did you do
that for?" he cried, with an angry dart of the keen eyes. "This is not
the first time I have drawn your blood. You KNEW I would not hurt you."

Hilda's face had grown strangely pale. But that was not all. I believe
I was the only person present who noticed one unobtrusive piece of
sleight-of-hand which she hurriedly and skilfully executed. When the
needle slipped from Sebastian's hand, she leant forward even as she
screamed, and caught it, unobserved, in the folds of her apron. Then
her nimble fingers closed over it as if by magic, and conveyed it with
a rapid movement at once to her pocket. I do not think even Sebastian
himself noticed the quick forward jerk of her eager hands, which would
have done honour to a conjurer. He was too much taken aback by her
unexpected behaviour to observe the needle.

Just as she caught it, Hilda answered his question in a somewhat
flurried voice. "I--I was afraid," she broke out, gasping. "One gets
these little accesses of terror now and again. I--I feel rather weak.
I don't think I will volunteer to supply any more normal blood this
morning."

Sebastian's acute eyes read her through, as so often. With a trenchant
dart he glanced from her to me. I could see he began to suspect a
confederacy. "That will do," he went on, with slow deliberateness.
"Better so. Nurse Wade, I don't know what's beginning to come over you.