The nurse made no comment, but led her patient downstairs at once, found the telephone number of the laboratory at which Rivière had his research-bench, and called for the connection.

"What do they say?" asked Elaine after a torturing wait.

"They ask me to hold the line."

Again a very long wait.

"What do they say?" asked Elaine again.

"Wait a little.... Yes, I'm here." ... "Mr Rivière has just left the laboratory."

"Where has he gone?" prompted Elaine.

"Where has he gone?" ... "They do not know."

"But I must find him!" cried Elaine. "Try his hotel, please."

The hotel people knew nothing of Rivière's whereabouts.