For half an hour they disported themselves in various ways while the Health Master, whose eyes were roving everywhere, made frequent entries in his book.

“All out now,” he ordered finally. “Come back in five minutes.”

Before the time was up, they were clustered at the door. Dr. Strong admitted them.

“Does the rehearsal begin now?” asked Bobs.

“It’s all over,” said the physician. “Look around you.”

“Ow-w-w!” wailed Bettina. “Look at Susan Nipper’s nose!”

That once inconspicuous feature had turned a vivid green.

“And the baseball is red,” cried Bobs.

“So’s my glove,” announced Julia.

Walking over to her, the Health Master caught her left hand and smeared it with blue crayon. For good measure he put a dab on her chin.