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the external skin ; and rests upon the eleetrid 

 organs, which fill more than two thirds of the 

 animal. The same vessels, which penetrate be- 

 tween the plates or leaves of these organs, and 

 which cover them with blood when they are cut 

 transversely, send out also numerous branches 

 to the exterior surface of the air-bladder. I 

 found in a hundred parts of the air of the swim- 

 ming-bladder four of oxygen and ninety-six of 

 azot. The medullary substance of the brain 

 displays but a feeble analogy with the albumin- 

 ous and gelatinous matter of the electric organs. 

 But these two substances have in common the 

 great quantity of arterial blood which they re- 

 ceive, and which is disoxidated in them; We 

 shall again remark on this occasion, that an 

 extreme activity in the functions of the brain 

 causes the blood to flow more abundantly to- 

 ward the head ; as the energy of the movement 

 of the muscles accelerates the disoxidation of 

 the arterial blood. What a contrast between 

 the multitude and the diameter of the blood- 

 vessels of the gymnotus, and the small space 

 occupied by it's muscular system! This con- 

 trast reminds the observer, that three functions 

 of animal life, which appear in other respects 

 sufficiently distinct, the functions of the brain, 

 those of the electrical organ, and those of the 

 muscles, all require the afflux and concourse of 

 arterial or oxygenated blood. 



