118 DAJTGEEOrS EFFECTS OF THE SHOCK. 



the animal's body. 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, also send 

 out 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 nitrogen. 

 The medullary substance of the brain displays but a feeble 

 analogy with the albuminous and gelatinous matter of the 

 electric organs. But these two substances have in common 

 the great quantity of arterial blood which they receive, and 

 which is deoxidated in them. We may again remark, on 

 this occasion, that an extreme activity in the functions of 

 the brain causes the blood to flow more abundantly towards 

 the head, as the energy of the movement of the muscles 

 accelerates the deoxidation of the arterial blood. What a 

 contrast between the multitude and the diameter of the 

 blood-vessels of the gynmotus, and the small space occupied 

 by its muscular system ! This contrast reminds the observer, 

 that three functions of animal life, which appear in other re- 

 spects 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. 



It would be temerity to expose ourselves to the first 

 shocks of a very large and strongly irritated gymnotus. If 

 by chance a stroke be received before the fish is wounded 

 or wearied by long pursuit, the pain and numbness are so 

 violent that it is impossible to describe the nature of the 

 feeling they excite. 1 do not remember having ever received 

 from the mscharge of a large Leyden jar, a more dreadful 

 shock than that which I experienced by imprudently placing 

 both my feet on a gymnotus just taken out of the water. 

 I was affected during the rest of the day with a violent pain 

 in the knees, and in almost every joint. To be aware of the 

 difference that exists between the sensation produced by the 

 Voltaic battery and an electric fish, the latter should be 

 touched when they are in a state of extreme weakness. The 

 gymnoti arid the torpedos then cause a twitching of the 

 muscles, which is propagated from the part that rests on the 

 electric organs, as far as the elbow. We seem to feel, at 

 every stroke, an internal vibration, which lasts two or three 

 seconds, and is followed by a painful numbness. Accord- 



