1854.] OF THE ROYAL INSTITUTION. 377 
associated with the memory of past years; followed by a tranquil 
state of imbecility, in which the most familiar faces and places are 
feebly recognised, or not at all. 
Divisions of insanity have sometimes been based on mere varieties 
of its mode of manifestation; as Pyromania, characterised by a 
propensity to set fire to buildings, &c.; Kleptomania, with a pro- 
pensity to theft. But in these cases, as in others where the pre- 
vailing tendency is to homicide, &c. a full investigation generally 
reveals wider impairment of the mind. Even the terms Monomania, 
or madness on one subject only, and Moral Insanity, or exclusive 
disorder of the moral feelings, have been far too extensively applied, 
and with some inconvenience; although their precise distinction is 
important in relation to crime. The occupations and amusements 
of the insane are often as fixed and determined as their more serious 
propensities. One man is always writing letters; another engaged 
in calculations; music alone delights others; and gardening and 
various work form to most of them the chief solace of their lives. 
Some are only active in devising mischief, and others, more dis- 
ordered in intellect, talk and write with curious incoherence. 
The state of Delusion, although common to so many cases, seems 
at first sight the most unaccountable of all the phenomena of mad- 
ness; but its nature affords perhaps the clearest illustration of what 
Unsound Mind really is. A mere definition of insanity seems im- 
possible. Unsound Mind, being the converse of Sound Mind, is a 
complicated state: for soundness of mind depends on the integrity 
and due relation to each other of many faculties; and it is the im- 
pairment of this integrity and the interruption of this due relation 
which constitutes unsoundness of mind. Such impairment may 
primarily exist in the sensations, or in the attention, or in the ima- 
gination, or in the memory, or in the affections and propensities ; 
but it is the degree of the impairment, and the obstruction it creates 
to comparing and judging, which make the mind unsound, and 
lead to irrational conclusions and conduct. The various shades of 
insanity depend upon the extent and nature of the impairment of 
any of the faculties, and the degree in which it interrupts their 
due and co-ordinate exercise, and impedes due comparison and con- 
sequently perverts the judgment. 
Several instances are recorded of persons being subject to ocular 
or aural hallucinations, or to both together, and for a length of time; 
but yet continuing sensible that they were only hallucinations. If 
the figures and voices are judged to be real in any case, the mind 
is on that subject unsound; and the consequences of this unsound- 
ness are often dangerous. When the hallucinations are recognised 
to be hallucinations, the person can compare them with realities, and 
his judgment concerning them is correct. When they are believed 
to be real, this power of comparing is lost, and the judgment is 
incorrect, and the resulting conduct is that of an insane person. 
The soliloquy of Macbeth, when, in the agitation of his mind be- 
fore the murder of the king, he imagines that a dagger appears 
