PART II.

THE PARTICULAR MORBID AFFECTIONS WITH

WHICH THE PRODUCTION OF PHANTASMS

IS OFTEN CONNECTED.

PART II.

CHAPTER I.

THE PATHOLOGY OF SPECTRAL ILLUSIONS.

"I lost all connexion with external things; trains of vivid visible images rapidly passed through my mind."-Sir Humphrey Davy on the Effects of the Nitrous Oxide.

HAVING explained certain divers opinions, ancient as well as modern, which have been entertained on the subject of apparitions, I ought, in due course, to state the particular notion which I may be inclined myself to adopt in the course of the present dissertation. Simply, then, it is the view to which I briefly adverted in the first chapter of this work, when treating of Nicolai's illusions; namely, that apparitions are nothing more than ideas, or the recollected images of the mind, which have been rendered as vivid as actual impressions. This is a view, however, that by no means originates with myself; it has entered into the disquisitions of

numerous metaphysical and pathological writers of the present day, among whom I might enumerate Hartly, Ferrier, Crichton, and Brown. Having stated, then, this hypothesis, my next object will be to give a general view of such causes as are principally instrumental in inducing those intense ideas which are currently recognised by the vulgar under the name of apparitions or phantasms. This should lead me to consider the case of Nicolai in a medical point of view. But before this can be done, it will be necessary to lay down a few general principles connected with this subject, which have hitherto met with little or no attention from physiologists. These arise from the explanation of certain states of the sanguineous system, in which a remarkable connexion between such states and an undue vividness of mental feelings appears to be established. It must be admitted, however, that such an inquiry is of extreme difficulty, and liable to innumerable sources of error, on which account a more than ordinary indulgence may be due to the attempt.

The essential view of the mind which I have adopted in preference to every other is that of the late much-lamented Professor of Moral Philosophy in the university of Edinburgh. Dr Brown, in considering the mind as simple and indivisible, conceives that every mental feeling is only the mind itself, existing

in a certain state.

In endeavouring then to obtain a correct notion of certain vital properties of the human frame, and of the relation which the immaterial principle of the mind may bear to them, I shall commence with that im