8 
Mr. Home’s Lecture 
of an inch, so that the object was magnified about 23 times ; 
and, that the results of the experiments might be as free from 
optical deceptions as the present state of our knowledge in this 
branch of science will admit, no appearance is described which 
Mr. Ramsden was not satisfied of having distinctly seen. 
The experiments performed with the single microscope were 
repeated with a double one, made by Mr. Ramsden, which 
magnified the object about 40 times ; but, in the double micro- 
scope, the appearances were indistinct, the reflection from the 
different glasses having thrown a confused glare upon the 
moist surface of the nerve. This circumstance led Mr. Rams- 
den to object to the use of compound microscopes, and to con- 
sider them as unfit for viewing objects of this kind. 
For the following reasons, the optic nerve of the horse was 
selected, as the most proper for the experiments. It is of a 
large size, and several inches in length. It is readily procured 
in a recent state ; as there are places in London where horses 
are allowed to be killed, and regular days in the week are fixed 
for that purpose. 
That the examination of the nerve might be made as soon 
as possible after the animal’s death, permission was procured 
from the man who superintends the killing of horses, to allow 
Mr. Clift to make the necessary experiments on the spot, the 
moment the horses were killed. Mr. Clift is the person in- 
trusted with the care of keeping in order the late Mr. Hunter’s 
collection in comparative anatomy, and is well qualified, from 
his anatomical knowledge, and a familiarity in looking at or- 
ganized parts through magnifying glasses, for an examination 
of this kind. These experiments were afterwards repeated by 
Mr. Ramsden and myself. From this mode of conducting 
