378 NOTICES OF THE MEETINGS [Feb. 17, 
before him, furnishes a remarkable illustration of the struggle be- 
tween delusion and reality, and the final triumph of the exercise 
of the comparing faculty. After the murder, he is less successful; 
and he believes that the ghost of Banquo fills a chair at the supper- 
table, although none of his guests are discomposed. For the time, 
and to that extent, he is then of unsound mind. 
This kind of illustration might be extended to cases in which not 
the senses, but the memory, or even the affections or propensities, 
are primarily affected: but it is always to be remembered, that it is 
the degree in which any faculty is impaired, and the extent of its 
influence over the judgment, and the form and tendency of the re- 
sulting actions, which justify interference. A man may think his 
figure changed, or his rank; or he may believe in monitory voices 
addressed to him alone; and yet his conduct may be harmless, and 
he may possess, as regards his property, a sound disposing mind. 
We endeavour, but without success, to find any intelligible 
explanation of the mental functions in health, or their disturbance 
in disease, in what anatomy or physiology have taught us respecting 
the arrangements and functions of nerves, or ganglia, or the brain. 
The distinct character and office of the vesicular or grey matter of 
the neryous substance, and the fibrous or white matter, have been 
clearly established: the recipient and governing character of the 
vesicular portion; and the messenger- office of the nerve-fibres, with 
its impassable limits as regards the offices of different fibres and 
different nerves. The functions of the spinal cord and the nerves 
proceeding from it; the reflex actions apparently originating in it, 
independently in ordinary cases, of the brain, and yet not dissociated 
from it; the offices of the complicated system called ganglionic or 
sympathetic, extending over important functions distinct from those 
of the spinal cord, and yet implicated with them, and not depending 
on the brain or will and yet, in various exigencies, influenced by 
them; the various arrangement of the vesicular matter in the 
ganglia, and in the spinal column, and in the separate masses at the 
base of the brain, and in the larger mass of the brain itself; have all 
been investigated with the utmost patience and skill. Many general 
conclusions, and some more minute and precise, have been arrived 
at. Nerves of motion have been distinguished from nerves of 
sensation, and traced to distinct portions of the spine; the function 
of respiration, indispensable to life, has been found to depend on the 
integrity of a point of grey or vesicular matter in the medulla oblon- 
gata; the co-ordinate motion of the muscles has been assigned as 
one of the uses of the cerebellum; the sense of sight has been 
proved to be lodged in the smaller masses called the corpora quad- 
ragemina ; and, in the higher animals, all these functions are known 
to be subservient to and dependent on the integrity of the brain for 
their continuance ; whilst to this superadded and large portion of 
the nervous system we assign the manifestation of the propensities, 
of the affections, and of the mental faculties of man; as, without a 
brain, there is no intellectual life. An influence extends from or to 
