199. The study of the speciality of mediums is necessary, not only for these, but for the invocator. According to the nature of the spirit whom it is desired to call, and the questions to be addressed to him, it is proper to choose the medium most suitable to the purpose; to take the first one at hand is to be ex- posed to the reception of incomplete or erroneous answers. Let us take a comparison from ordinary- usage. An editorial, even a simple copy, would not be confided to the first comer, because he might know how to write. A musician wants a bit of singing exe- cuted, of his own composition ; he has at his disposal several singers, all skillful; yet he does not take by chance: he will choose for his interpreter the one whose voice, expression, all whose qualities, in fact, best answer to the nature of the music. The spirits do the same with regard to the medium, and we should do as do the spirits.
It is, besides, to be remarked, that the shades that mediumship presents, and to which others might be added, are not always related to the character of the medium ; thus, for instance, a medium naturally gay and jovial, might habitually have grave, even severe communications, and vice versa; here, again, is an evident proof that he acts under a foreign influence. We shall return to this subject in the chapter that treats of the Moral Influence of tlie Medium.