4. According to the Physical Qualities of the Mediums.
194. Calm Mediums. They always write with a cer- tain slowness, and without experiencing the least agi- tation.
Rapid Mediums write with a rapidity greater than they could voluntarily, in the ordinary state; spirits communicate with them with the velocity of lightning it might be said, they have a superabundance of fluid, which permits their instantaneous identification with the spirit. This quality has sometimes its incon- venience, the rapidity of the writing making it very difficult to read for any other but the medium.
" It is also very fatiguing, for it expends too much fluid uselessly."
Convulsive Mediums. They are in an almost feverish state of over-excitement; their hand, and sometimes their whole person, is agitated with a trembling they cannot master. The primary cause is, without doubt, in the organization, but it depends also much on the nature of the spirits who communicate with them ; good and benevolent spirits always make a gentle and agreeable impression ; the bad, on the contrary, a painful one.
" Mediums should use but rarely their medianimic faculty, where the too frequent use of it may affect the nervous system." (Chapter on Identity, distinction between good and bad spirits.)