s he leaned forward, with parted
lips and a hand on each knee, betrayed an interest so abnormal that it
was odd that Basterga did not notice it.

Instead, "I found that he had made," the scholar replied quietly, "as
far back as the tenth century the same experiment which I had just
completed. And with the same result."

"He obtained the substance?"

Basterga nodded.

"And discovered? What?" Blondel asked eagerly. "Its use?"

"A certain use," the other replied cautiously. "Or, rather, it was not
he, but an associate, called by him the Physician of Aleppo, who
discovered it. This man was the pupil of the learned Rhazes, and the
tutor of the equally learned Avicenna, the link, in fact, between them;
but his name, for some reason, perhaps because he mixed with his
practice a greater degree of mysticism than was approved by the Arabian
schools of the next generation, has not come down to us. This man
identified the product which had defied Ibn Jasher's tests with a
substance even then considered by most to be fabulous, or to be
extracted only from the horn of the unicorn if that animal existed. That
it had some of the properties of the fabled substance, he proceeded to
prove to the satisfaction of Ibn Jasher by curing of a certain incurable
disease five persons."

"No more than five?"

"No."

"Why?"

"The substance was exhausted."

Blondel gasped. "Why did he not make more?" he cried. His voice was
querulous, almost savage.

"The experiment," Basterga answered, "of which it was the product was
costly."

Blondel's face turned purple. "Costly?" he cried. "Costly? When the
lives of men hung in the balance."

"True," Basterga replied with a smile; "but I was about to say that,
costly as it was, it was not its price which hindered the production of
a further supply. The reason was more simple. He could not extract it."

"Could not? But he had made it once?"

"Precisely."

"Then why could he not make it again?" the Syndic asked. He was
genuinely, honestly angry. It was strange how much he took the matter to
heart.

"He could not," Basterga answered. "He repeated the process again and
again, but the peculiar product, which at the first trial had resulted
from the precipitation, was not obtained."

"There was something lacking!"

"There was something lacking," Basterga answered. "But what that was
which was lacking, or how it had entered into the alembic in the first
instance, could not be discovered. The