270 
DR. DAVY’S ACCOUNT OF SOME EXPERIMENTS 
approach to it ; but I have never witnessed it in a satisfactory manner in the 
fresh fish. Mr. Hunter inspected large fishes which had been preserved in 
spirits. The partitions of the columns in them might have been more visible, 
(supposing them to exist,) from the action of the spirit on the membrane, and 
from the greater size of the specimen ; or they might have been formed after 
death, in the spirits, by a slow deposition of the animal matter contained in 
the columns. 
Next to the nature of the substance of the electrical organs, the electrical 
nerves have occupied my attention. Their three great trunks have been accu- 
rately described by Mr. Hunter ; but this distinguished anatomist has very 
briefly noticed their distribution, which is curious, and deserving, I believe, of 
minuter investigation. I shall attempt little more than an outline of what I 
have observed in some dissections conducted with considerable care. 
In examining the brain, proceeding from the anterior to the posterior por- 
tion, after passing the first, second, third, and fourth pair of nerves, or the 
olfactory, optic, motor and pathetic nerves of the eye, the fifth pair is seen 
issuing from the medulla oblongata, or posterior tubercle of the brain *. After 
quitting the cranium, (confining the description to one side,) it proceeds up- 
wards, divides into two large branches, which go to clusters of mucous glands 
situated in the front of the head and at the anterior margin of the electrical 
organs, and they appear to be confined to these parts. The next pair, the first 
electrical, rises close to the preceding, just behind it, and in passing out of 
the cranium is firmly connected with it ; and also where it passes out, a por- 
tion of medullary matter proceeds from it into a cavity filled with fluid, in 
the cartilage adjoining, which there is reason to consider as the cavity of the 
organ of hearing, and the medullary matter the nerve of hearing. After this, 
in passing outwards, it divides into three small branches and two large ones. 
Of the former, one proceeds to the gills, another to the adjoining muscles, and 
the third to the mouth. Of the great branches, one ascends, and sweeping 
round the margin of the electrical organ is distributed to the mucous glands 
which abound there, and where some of its twigs inosculate with twigs of the 
former nerve. The other great branch, which is inferior, enters the electrical 
* The nerves of the fourth pair are so very small and tender, that it is difficult to demonstrate them, 
excepting in old and large torpedos. 
