Those who are new to the observance and/or study of mediumship sometimes perceive the medium to be almost as if a mere microphone for a communicating Spirit,  transmitting a message without influencing the content or style of that message in any way.   In reality however, a medium acts more like an interpreter when exercising his role as an intermediary instrument used by the Spirit.  Inevitably then, the message that was communicated by the Spirit will suffer, to some greater or lesser degree, an influence from that medium.  This is similar to the way that  a foreign language interpreter inevitably influences the translation of a message from the speaker of one language to the listener or reader of another.   The accuracy of the message always depends on the preparation, skills, and character of the messenger.

The Spirits even tell Kardec that if the medium "is not properly tuned in to [the Spirits], he may alter their replies and assimilate them to his own ideas and propensities", adding however, that this medium "does not influence the Spirits themselves; he is only an inexact interpreter."  They remind us that "the same thing occurs amongst [humans] when a message is conveyed through a careless, hostile, or unfaithful messenger."  Knowing that mediums vary in the nature of their faculties and can thus be more or less active/passive, more or less conscious/unconscious during the moment of the communication (see "Speaking and Writing Mediums" on menu bar at left) you may wonder how this influence works in the case of the passive, unconscious medium.  Kardec asked about this ("Mediums' Book, item 223 Q.9), to which the Spirits explained that "In order to transmit an intelligent communication, the medium just have an intelligent intermediary, and this intermediary is furnished by the Spirit of the medium....... The medium is passive when he does not mingle his own ideas with those of the communicating Spirit, but he is  never an absolute nullity."

Naturally, we can understand why the Sprits confirm for Kardec that certain spirits have a preference for certain mediums, as they "seek for interpreters [those who are]  in sympathy with themselves and able to transmit their thought correctly."

The influence of a medium upon the message of the communicating Spirit can be of a mental/intellectual nature and/or of a moral nature.  Here we will look at the functioning of both types.

 The Mental/ Intellectual Influence

The Spirit, Odilon Fernandes (in "We Are All Mediums), refers to this kind of influence as a "mental mirror."  he writes, "Being an interpreter of the Spirit's thought, it is only natural that the message transmitted brings something from the medium, just as a mirror does when reflecting an image, according to its possibilities and conditions.  A dull or broken mirror, obviously, will reflect distorted images, although the object remains correct.  Therefore, the medium's mental mirror is of fundamental importance, in the process of intellectual communications."

The important point to understand with respect to the intellectual influence of the medium relates to the way in which the medium's mind serves as a kind of "toolbox" for the Spirit who desires to communicate.  Kardec writes, "Spirits derive not ideas, but the material necessary for expressing their ideas, from the medium's brain; consequently, the richer the brain is in materials, the easer it is for them to communicate through its processor."

These necessary materials refer to the knowledge of the medium on a given topic, his skills in a style of expression, his writing abilities (if a written communication), and even (if such be the need) his knowledge of a particular language* (*keep in mind that Spirits communicate to one another via thought and need no language, yet as humans we still need letters and words to understand a thought).  Such intellect and abilities may be possessions of the medium in the present life, or they may be latent acquisitions derived from a previous existence.

The following excerpt from a Spirit dissertation found in "The Mediums' Book" (item 225) explains how the intellectual capabilities and characteristics of the medium influence the ease of the Spirit's ability to communicate as well as the final message that results from this mediumistic exchange:

"Through a medium whose intelligence has been sufficiently developed by the experiences of present and anterior lives, we are able to flash our thought, instantaneously, from our soul to his, by a faculty inherent in the very nature of the soul.  We are able to do this, in such a case, because we find, in the medium's brain, the elements fitted to give to our thought its appropriate clothing of words, whether the medium be intuitive, semi-mechanical, or purely mechanical.  Thus, whatever may be the diversity of the Spirits who communicate through a given medium, the communications obtained by him, though proceeding from various Spirits, usually present a characteristic peculiarity of form and color due to his own personal individuality.  Although the thought transmitted may be entirely foreign to him, although the subject treated of may be beyond his usual range of ideas, and although what he says may not have proceeded in any way from his own mind, the form of our communication will, nevertheless be modified by the influence of the qualities and properties which constitute his own personal individuality.

It is precisely as when you look at landscapes or other objects through colored spectacles, whether green, white, blue, or red; though the landscapes or other objects thus seen are altogether different from one another, they all assume, nevertheless, a uniform tint imparted to them by the color of the glass through which you see them.  We are the light, lighting up those landscapes or other objects, moral or philosophical, through glasses of various colors, so that our luminous rays (forced as they are to pass through media more or less colorless and translucent, that is to say through mediums more or less intelligent and manageable) cannot reach the object we desire to light up, without borrowing the tint, that is to say, the peculiar personal form of the medium.

Let me illustrate my meaning by yet another comparison.  We, Spirits, are like musicians who wish to play an air of our composing, and who may have, at hand, either a piano, a harp, a violin, a bassoon, or a flute.  It is evident that we might execute our air on either of these instruments, and that it would be understood by our auditors, no matter on which instrument we played it;  although the various instruments differ greatly in the quality of the sound they emit, our composition, on whichever instrument we played it, would be identically the same, except in the special quality of the tone derived from the nature of the instrument employed.  But if we had at our disposal only a penny whistle, we should find it very much more difficult to execute our air so that our audience could comprehend it.

In the same way, when we are obliged to make us e of unadvanced mediums, our work is much more complicated, difficult, and tedious, because, in such a case, we are forced to employ inadequate means;  and because we are then compelled, so to say, to set up our thoughts, as though by putting them into type, communicating them, not only word  by word, but also letter by letter, which is tiresome and fatiguing for us, and constitutes a restraint on the rapidity and completeness of our manifestations."

 The Moral Factor

The moral influence of the medium refers to the law of moral affinity which says that by the moral nature of their thoughts and behaviors mediums, (like all of us) attract Spirits of a like character and determine the kind of Spirits who will habitually communicate through them and influence their thoughts through intuitive suggestions.

Similarly, the degree of tuning obtained between the medium and the Spirit affects the medium's ability to capture the Spirit's communication.  That degree of tuning, in turn, stems from the affinity between the two.  When there is no affinity between them, the Spirit of the medium becomes an antagonist and produces resistance;  he is an unwilling interpreter.  Should a communication occur, the interpretation will most likely be unfaithful.  Likewise, there is a danger, especially with non-vigilant mediums, for the involuntary substitution of the medium's own ideas for that which the communicating Spirit endeavor's to suggest. 

Again, we present an excerpt from a dissertation made by the same Spirit that we quoted above (found in item 230).  In comparing the Spirit communicating through a medium to a telegraph clerk acting on his machinery, this Spirit writes:

"Just as atmospheric influences act upon and sometimes disturb the transmission of a telegraphic dispatch, so the moral influence of the medium acts upon, and sometimes disturbs, the transmission of our dispatchers from the world beyond the grave, when we are obliged to transmit those dispatches through a medium who is sympathetically or intellectually opposed to their tenor.

This opposing influence is, however, often annulled by the energy of our will, whereby messages of high philosophic import and elevated morality are sometimes conveyed through mediums but little fitted for their transmission, while on the other hand, very unedifying communications are occasionally introduced through mediums who are grieved and ashamed to have been used for their transmission.

But not withstanding these occasional exceptions, it may be affirmed, as a general proposition, that incarnate Spirits attract discarnate Spirits of similar nature and advancement, and that Spirits of high degree rarely communicate through mediums who are bad conductors, when they have at hand good medianimic machinery, that is to say, good mediums."

 A Spirit's Choice

In order for a Spirit to truly express his desired message through the instrument of a medium, that Spirit needs a medium with whom it shares a fluid affinity, a strong moral affinity, and an intellectual likeness with respect to ideas, knowledge, and vocabulary.  In the absence of a well-prepared medium, a Spirit will (when needing to communicate) use another medium, despite his or her limitations.  However, as a general rule, the Spirits will always seek out and work with the medium that is best able to serve as their intermediary and most accurately convey their message.  It will also be noted that Spirits prefer the help of a medium with good will and limitations than one who is well-prepared but emotionally unstable or morally unfit.

 A Medium's Responsibility

The above explanations leave us with important implications for the medium who wishes to receive communications from good Spirits.  It is important for such a medium to engage in edifying studies that allow him to progress in his intellectual capabilities and thus improve the "mental toolbox" that he has to offer to enlightened Spirits.   In particular, the regular study of the Doctrine's teachings regarding mediumship will improve his knowledge of mediumistic mechanisms and help him to improve his capture and transmission of the Spirits' messages and sentiments.  Likewise, his regular study of the Gospel and related works will help strengthen his defense against inferior Spirits and even against his own inferior tendencies.   In addition, it is imperative for the medium to be vigilant of his thoughts and behaviors on a continuous basis, making continuous efforts to improve his moral condition. This serves the medium not only in the Spiritual advancement for which he is ordained under natural law,  but also in the protection from negative influences as well as the attraction of friendly, mentoring Spirits that find in him a faithful partner for the fulfillment of their task.

Fernandes, Odilon (Spirit Author) / Baccelli, Carlos (Medium). "Mental Mirror". We Are All Mediums.  Trans.Coelho, Públio Lêntulus Vicente. Votuporanga- SP, Brazil. Casa Editora Espírita "Pierre-Paul Didier". 2001 73-76. 

Fernandes, Odilon (Spirit Author) / Baccelli, Carlos (Medium). "Words and Thoughts". We Are All Mediums.  Trans.Coelho, Públio Lêntulus Vicente. Votuporanga- SP, Brazil. Casa Editora Espírita "Pierre-Paul Didier". 2001 77-80. 

Fernandes, Odilon (Spirit Author) / Baccelli, Carlos (Medium). "In The Absence of Another Medium". We Are All Mediums.  Trans.Coelho, Públio Lêntulus Vicente. Votuporanga- SP, Brazil. Casa Editora Espírita "Pierre-Paul Didier". 2001. 89-92. 

Kardec, Allan. "The Action of The Medium in Obtaining Spirit Manifestations" and "Mental and Moral Influence of the Medium." The Mediums' Book. 2nd ed (1st edition FEB). Trans. Anna Blackwell (translated 1876). Ed. Livraria Espírita Allan Kardec. Brasilia-DF, Brazil:  Federação Espírita Brasileira [Brazilian Spiritist Federation}. 1986. 283-253 and 254-269.