56 THE ENGINES OF THE HUMAN BODY 



of the neck. Makers of modern telescopes have imitated 

 the method Nature invented when fixing the human 

 head to the spine. Their instruments are mounted with 

 a double joint — one for movements in a horizontal plane, 

 the other for movements in a vertical plane. We thus 

 see that the young engineer as well as the student of 

 medicine can learn something from the construction of 

 the human body. 



In low forms of vertebrate animals like the fish and 

 frog, the head is joined directly to the body, there being 

 no neck. 



