“A yellow card, Burbank? Are you sure it was not a white one?”

“Positive, sir. I thought it was white for a moment; but when he held it in his hand, I noted that it was yellow. A pale yellow — almost white.”

“Where is the man now?”

“At the Pink Rat. He has been drinking a great deal.”

“All right, Burbank. Let him stay there. Go off duty. I’ll let you know when you are needed.”

Lamont Cranston sat in thought for a few minutes after he had hung up the receiver. Then he smiled.

“A yellow card,” he murmured. “Yellow — almost white. Volovick has been drinking. Rather a bad practice if he is engaged in active work.”

He drew a pad from his pocket, and wrote:

Black — A meeting to-night. Gray — Meeting: do not come if in danger. White — Work ended. No more meetings.

He paused momentarily; then added: