mixed origin. It can hardly be otherwise, seeing how intimate is the structural and functional connection between the nerve-centres of thought and sense, and how likely so closely' connected nerve-centres are to sympathize in suffering when the one or the other is disordered.
No one pretends that a person who, laboring under hallucinations, knows their true nature, as Nicolai did, is insane; but it is often said that he has passed the limits of sanity and must be accounted insane when he does not recognize their real nature, and believes in them and acts upon them. But the examples which I have given prove this to be too absolute a statement. I should be very loath to say that either Mohammed or Luther was mad. When the hallucination is the consistent expression of an earnest and coherent belief, which is not itself the product of insanity, it is no proof of insanity, although it may indicate a somewhat unstable state of the brain, and warn a prudent man to temper the ardor of his belief. When, however, a person has hallucinations that are utterly inconsistent with the observation and common-sense of the rest of mankind; when he cannot correct the mistakes of one sense by the evidence of another, although every opportunity is afforded him to do so; when he believes in them in spite of confuting evidence, and when he suffers them to govern his conduct, then he must certainly be accounted insane: he is so much out of harmony of thought and feeling with his kind that we cannot divine his motives or reckon upon his conduct, and are compelled to put him under restraint. Persons of this class are apt to be troublesome and even dangerous; believing that they are pursued by a conspiracy, hearing the threatening voices of their persecutors wherever they go, seeing proofs everywhere of their evil machinations, smelling poisonous fumes, feeling the torture inflicted by concealed galvanic wires, they endeavor to protect themselves by all sorts of devices—appeal to the magistrates and the police for assistance, become public nuisances in courts of justice, are, perhaps, driven at last, either from despair of getting redress, or by the fury of the moment, to attack some one whom they believe to be an agent in the persecution which they are undergoing. Some of them hear voices commanding them peremptorily to do some act or other—it may be to kill themselves or others—and they are not unlikely in the end to obey the mysterious commands which they receive.
Having said so much concerning the causation and character of hallucinations, I ought, perhaps, before concluding, to say something about the means of getting rid of them. Unfortunately, it is very little that I can say, for, when once they have taken firm hold of a person, they are seldom got rid of. When they occur during an acute case of insanity, where there is much mental excitement, they certainly often disappear as the excitement passes off, or soon afterward, just as they disappear when the delirium of fever subsides; but, when they have become chronic, they hold their ground in defiance of every