Photo credits: Picture
from book, "Estudando
a Mediunidade"

You may wonder if one has to be an ostensive medium to give passes.  The answer is no. Jacob Melo (a Spiritist researcher of magnetism) writes, "The pass givers- in general- would be those who do not possess an ostensive mediumship, but who still can serve as a channel for the spirits in the transit of spiritual fluids to the material realm, or they could even be the so-called [human] magnetizers who find, in themselves, the necessary fluid generating forces.  The pass-giving mediums are those who do possess a more ostensive mediumistic sensitivity and, as such, perceive, register, and act jointly and knowingly with the spirits."  

There is still yet another distinction to be made, which involves the, albeit rare, "curing mediums"*, which Kardec, in "The Mediums' Book", refers to as those who have the power of curing disease or relieving pain, by the imposition of hands or by prayer.  While they also make use of the action of magnetic fluids, the methods are different from the direct donation employed by the pass-givers.  Spiritist author, Eliseu Rigonatti, explains that these mediums "radiate an abundant amount of fluids of a highly magnetic power, which are used by the healing/curing spirits for the production of cures and the creation of fluidic medicines and treatments", used for the benefit of incarnate patients.   Kardec writes (in "Genesis"):

The ability to heal through fluidic interaction is very common and can be developed through exercise, but the instant cure via imposition of the hands is much more rare and its appearance in the maximum degree should be considered exceptional.  Even so, in diverse periods throughout history, and amidst almost all peoples, there have been individuals who have had the faculty in an eminent degree.

He later states:

The effects of fluidic action on the patients are extremely varied.  Sometimes, it is slow and requires prolonged treatment, as in regular magnetism; other times, it is fast, like an electric current.  There are even people who have such an ability that they can operate instant cures in some patients, via the imposition of the hands, or even exclusively through an act of will.  Between the two extremes of this faculty, there are infinite shades.  All the cures of this type, however, are varieties of magnetism and differ only in the intensity and speed of action.  The basic, underlying principle is the same: the fluid, acting in its role as a therapeutic agent and the effects of which depend on the quality of the fluid and other special circumstances.