108 BRITISH SERPENTS. 



The main artery to the liver is seen running along one 

 margin of that organ, and the vessels to the lung can 

 also be traced. Eespiration in adders is very slow, 

 and very difficult to count, but I once satisfied myself 

 that a particular adder took seven breaths in a minute. 

 They can, however, do with very little air, and have 

 been known to survive in a closed bottle for a 

 considerable time. 



