The door flew open with a bang. A sickly perfume swept out to them.

"Matches! matches, Rob! this way!"

They went stumbling in. Robert Cairn took out a box of matches--and
struck one. His father was further along, in the centre building.

"Your knife, boy--quick! _quick_!"

As the dim light crept along the aisle between the orchids, Robert
Cairn saw his father's horror-stricken face ... and saw a vivid green
plant growing in a sort of tub, before which the doctor stood. Four
huge, smooth, egg-shaped buds grew upon the leafless stems; two of
them were on the point of opening, and one already showed a delicious,
rosy flush about its apex.

Dr. Cairn grasped the knife which Robert tremblingly offered him. The
match went out. There was a sound of hacking, a soft _swishing_, and a
dull thud upon the tiled floor.

As another match fluttered into brief life, the mysterious orchid,
severed just above the soil, fell from the tub. Dr. Cairn stamped the
swelling buds under his feet. A profusion of colourless sap was
pouring out upon the floor.

Above the intoxicating odour of the place, a smell like that of blood
made itself perceptible.

The second match went out.

"Another--"

Dr. Cairn's voice rose barely above a whisper. With fingers quivering,
Robert Cairn managed to light a third match. His father, from a second
tub, tore out a smaller plant and ground its soft tentacles beneath
his feet. The place smelt like an operating theatre. The doctor swayed
dizzily as the third match became extinguished, clutching at his son
for support.

"Her life was in it, boy!" he whispered. "She would have died in the
hour that it bloomed! The priestesses--were consecrated to this....
Let me get into the air--"

Mr. Saunderson, silent with amazement, met them.

"Don't speak," said Dr. Cairn to him. "Look at the dead stems of your
'Mystery.' You will find a thread of bright hair in the heart of
each!..."

* * * * *

Dr. Cairn opened the door of the sick-room and beckoned to his son,
who, haggard, trembling, waited upon the landing.

"Come in, boy," he said softly--"and thank God!"

Robert Cairn, on tiptoe, entered. Myra Duquesne, pathetically pale but
with that dreadful, ominous shadow gone from her face, turned her
wistful eyes towards the door; and their wistfulness became gladness.

"Rob!" she sighed--and stretched out her arms.

CHAPTER XXV

CAIRN MEETS FERRARA

Not the lea