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THE INTERNAL ENVIRONMENT OF THE BODY 



Part III 



i 



Fig. 10.1. Kittens falling and preparing to land. The grace and flexibility of their 

 muscles are unsurpassed. The nervous system controls the movements that the 

 muscles accomplish with the skeleton as their tool. (Photograph by Ylla. Courtesy, 

 Rapho-Guillumette Studio, New York, published in Cats, London, Harvill Press.) 



I 



