' * - AS AA AAAAtcT C A\X ite, 
122 Mr. Todd's observations and experiments 
important an observation, that it may be repeated with pro- 
priety. 
The shocks received from the torpedos which I examined. 
Were never sensible above the shoulder, and seldom above 
the elbow-joint. The intensity of the shock bore no relation 
to the size of the animal (sensation being the only measure 
of intensity), but an evident relation to the liveliness of the 
animal, and vice versa. The shocks generally followed simple 
contact, or such irritation as pressing, pricking, or squeezing, 
sometimes immediately, and sometimes not until after 
frequent repetition. Not unfrequently, however, animals 
apparently perfectly vivacious suffered this irritation without 
discharging any shock. There appeared no regularity of 
interval between the shocks. Sometimes they were so fre- 
quent as not to be counted ; at other times, not more than 
one or two have been received from one animal; and, in a 
few instances, it has been impossible by any irritation to elicit 
shocks from some of them. When caught by the hand, they 
sometimes writhed and twisted about, endeavouring to extri- 
cate themselves by muscular exertion, and did not, until they 
found these means unavailing, discharge the shock. In many 
instances, however, they had recourse to their electrical power 
immediately. 
The electrical discharge was, in general, accompanied by 
an evident muscular action. This was marked by an apparent 
swelling of the superior surface of the electrical organs, par- 
ticularly towards the anterior part, opposite to the cranium, 
and by a retraction of the eyes. It was so evident, that when 
the animal was held in the hand of another person, I was 
often able to point out when he received the shock. In this. 
