This same white figure which they had both now glimpsed had crossed the
road, flying as it was now toward the trenches. The werwolf, as the
superstitious French peasants declared it to be, crossed both to and
from the battle line; for it was frequently seen.

It was of this mystery Henriette Dupay had spoken in the library of the
chateau that very afternoon. The Dupays believed absolutely in the
reality of the werwolf.

Only, they were not of those who connected the "Thing" with the lady of
the chateau. Although Ruth Fielding had reason to believe that the
police authorities trusted the Countess Marchand and were sure of her
loyalty, many of the peasants about the chateau believed that the
werwolf was the unfortunate countess herself in diabolical form.

And even Ruth could not help feeling a qualm, as she saw the
fast-disappearing creature--ghost or what-not--that fled into the
darkness.

"Gosh!" murmured the slangy Charlie Bragg. "Enough to give a fellow
heart-disease. I thought I was going to run it down."

"I wonder," said Ruth slowly, as he again started the car, "if it would
not have been a good thing if you had run it down."

"Can't bust up a ghost that way, Miss Ruth," he returned, beginning to
chuckle again.

"Talk sense, Charlie," she urged, forgetting for the moment the subject
of the suspicion resting upon Tom Cameron and giving her mind to this
other mystery. "You know, I've an idea this foolishness about a white
wolf can be easily explained."

"Go ahead and explain," he returned. "I'm free to confess it's got me
guessing."

"I believe it is the big greyhound, Bubu, that belongs to the Chateau
Marchand. It is sent on errands to and from the frontier."

"Canine spy?" chuckled Charlie.

"I don't know just what he does. But I did think that the old serving
woman, Bessie, that the countess brought with her from Mexico so many
years ago, knew all about Bubu's escapades. But Bessie is not at the
chateau now."

"Oh," said Charlie, "she was the woman who went off with those two
crooks who helped your friend, Mrs. Rose Mantel, rob the Red Cross
supply department."

"Not _my_ friend, I should hope!" Ruth said sharply, for the matter
Charlie touched upon was still a tender subject with the girl.

Her mind dwelt for a moment upon the presence of Major Henri Marchand
at the chateau. He was there, and the greyhound, Bubu, was running at
large again at night. Was there not something signi