51. What is the "bends" and how do divers become afflicted 

 with it? 



High pressure at depth causes some of the nitrogen in a diver's body 

 tissue to dissolve in his blood. If he ascends too rapidly, bubbles will 

 form in the blood and collect in his joints and bone marrow, causing 

 the extremely painful condition known as the "bends." It is not 

 ordinarily fatal unless bubbles collect in the spinal cord or brain, but the 

 pain will continue for several days unless the diver is put under pres- 

 sure and decompressed gradually; if the condition goes untreated there 

 will be bone damage. 



After a long dive, a diver is returned to normal pressure gradually so 

 that nitrogen in the blood may be released through the lungs, avoiding 

 the "bends." 



Bond, George F. 



"Medical Factors in Diving Safety," Signal, October, 1965. 

 Gaskell, T. F. 



World Beneath the Oceans, American Museum of Natural History, 



1964. 

 Rebikoff, Dimitri 



Free Diving, E. P. Dutton and Company, 1956. 



59 



