272. Invocations often present more difficulties to mediums than spontaneous dictation, especially when exact answers are wanted to circumstantial questions; For that end special mediums are required at once flexible and positive; and we have seen (No. 193), that these last are quite rare, for, as we have said, the fiuidic relations {rapports) are not always instantaneously established with the first spirit comer. It is, therefore, best that mediums should not attempt special invocations, until assured of the development of their faculty, and of the nature of the spirits who assist them ; for with those who are badly surrounded, the invocations could have no character of authority.
