248 
SIR CHARLES BELL ON THE NERVOUS SYSTEM. 
to remark, that between the opinions taught in the schools, and the inferences to be 
deduced from the distribution of these nerves, there was no correspondence. Why do 
six nerves pass into the orbit? Why should two nerves descend into the nose? Why 
should three nerves penetrate the coats of the eye ? Why should some of these nerves 
have ganglions on them and others none ? If it be correct, that the brain is the offi- 
cina spirituum, and gives out a common influence through the nerves, what is the 
meaning of this intricacy in the distribution of the nerves ? I then held the following 
argument. Common occurrences, and the symptoms of disease, correspond with the 
anatomical facts, while they are adverse to the received opinions. 
1. A catarrhal inflammation of the membrane of the nose is attended with the loss 
of the sense of smelling, and the increase of the sensibility to common irritation. 
Does not this imply a difference in the functions of the first and of the fifth nerve ? 
and that their offices are not transferable ? 
2. In performing the operation of couching the cataract, as the needle touches the 
surface of the eye, it pricks it, and the patient feels a pain similar to what he would 
do were the skin pricked ; but as the needle passes through the retina, he has a flash 
of fire. Does not this imply a difference of sensibility from the same injury, or the 
same impulse? Do we not perceive that there is a nerve of vision, and a nerve appro- 
priated to the external surface ? 
3. When we receive a blow on the head, does not the same vibration affect the 
nerves of sense differently? In the ear, it produces sound as of the ringing of bells; 
in the eye, corruscations of light. 
4. But here is the third nerve passing into the eye ; is it also for sensation, or is 
there a motion of the iris to be established in relation to the sensorial impressions? 
5. Shall we admit the interpretation, that the brain is the common sensorium, and 
that the peculiar office and sensibility of the external organ of sense result from the 
organization of the extremity of the nerve ? On the contrary, it is capable of proofj 
that the trunk of a nerve, even of sense, receives and conveys an impulse which gives 
rise to the ideas belonging to that sense and to no other. The agony which ac- 
companies the extirpation of the eye, forbids us to expect an account of the sensation 
experienced when the optic nerve is cut across. But we have other proofs. When 
the pudic nerve is exposed, the sensation is that which is appropriate to the glans. 
The subject was followed up in the succeeding lecture ; which, in order, was a 
demonstration of the nerves of the tongue — where three nerves are given to one 
organ. 
Such, then, were the suggestions from anatomy and common experience, which led 
me to the conclusion, that nerves have appropriate properties ; and that these pro- 
perties are derived from the roots of the nerves, that is, their origins in the brain. 
To verify this view, I was first led to make experiments on the brain. These proved 
futile ; and I then thought of determining the matter by experiments on the spinal 
marrow, and the roots of the spinal nerves. 
