164. We give this designation to persons who are able to recognise the presence of spirits by a vague impression, a sort of shuddering sensation, running through their whole body, and for which they cannot account. This variety of medianimity has no very decided characteristic. All mediums being necessarily impressionable, this quality maybe regarded as being general rather than special; but it is an indispensable condition of all other forms of medianimity. It is different from purely physical and nervous impressionability, with which it must not be confounded; for there are persons whose nerves are by no means delicate, and who are nevertheless affected by the presence of spirits, while others, whose nerves are very irritable, have no perception of their presence.

The faculty of perceiving the presence of spirits is developed by habit, and may become so subtle as to enable one who is endowed with it to recognise, by impression, not only the good or evil nature of the spirit at his side, but even his individuality; just as a blind man, by an undefinable faculty of perception, recognises the approach of such and such a person, so a medium of the kind we are considering recognises the presence of certain spirits. A good spirit always produces an agreeable impression; an evil spirit, on the contrary, produces an impression that is painful and disagreeable and causes a feeling of anxiety; it seems to bring with it, so to say, an odour of impurity.