With a book on her lap, and her own round white arm going through all manner of queer evolutions, she was placidly repeating, "Deltoides, Biceps, Triceps, Pronator, Supinator, Palmanis, Flexor carpi ulnaris" "Here's Flexis what-you-call-ums for you," interrupted a voice, which began in a shrill falsetto and ended in a gruff bass, as a flushed, dusty, long-legged boy burst in, with a bleeding hand obligingly extended for inspection.