10 
Mr. Home’s Lecture 
verse sections were examined in different parts of the nerve, 
near the brain, towards the middle, and nearer the eye: of 
these experiments the following are the results. In all the sec- 
tions, the nerve appeared to be made up of the same sub- 
stances ; but the size and number of the opaque parts differed 
very much. They have been stated, near the eye, to be 600 ; 
about the middle of the nerve, they were 150; and, near the 
brain, between the origin and union of the two nerves, they 
were only about 40. As they became larger, they were less 
regular in their shape, and had less of a circular form ; nor 
were they uniform, some appearing very large, with one or 
two smaller placed between them. 
After having succeeded in this examination of the nerve 
transversely, an attempt was made to investigate its structure 
in a longitudinal direction. To do this, a portion of the nervous 
pulp had its coat, formed by the dura mater, along with a thin 
vascular membrane which lines it, carefully removed for about 
an inch in length : the external surface of the pulp was then 
examined with a magnifying glass ; the structure was evidently 
fasciculated, but the fasciculi did not run parallel to one ano- 
ther; they seemed to unite together and separate again, in 
such a manner that any one of them could not be traced for 
half an inch in length, without being lost in the neighbouring 
part. When thin sections were examined in the field of the 
microscope, they put on the same appearance : this was equally 
the case, whether the part examined was near the centre or 
circumference of the nerve. The fasciculi were largest in that 
part of the nerve near the brain, and smallest towards the eye. 
Great pains were taken to ascertain whether the fasciculi were 
made up of continued fibres, or of small parts unconnected. 
