But the Church has not defined every expression of truth, though she holds the key to all truth. She points to the light which illumines our night; she declares the stars whence that light issues directly or by reflection; but she does not always indicate where the rays of the one body begin to mingle with those of the other, or what precise elements determine the motion or stability of each. Only when there are conflicts or threatened disturbances of the centres of attraction and repulsion she reaches out her anointed hand, informed with the magic power of her Creator and founder, and directs the courses of bodies that otherwise would clash unto mutual destruction. Hence the freedom of investigation allowed the Catholic student of the Scriptures is limited only by the rules of faith taught by the same divine Teacher who watches over the spoken and written revelation alike. And as, in cases where we have not the express command of a superior, we interpret his will by his known desires and views in other respects, so in the interpretation of those parts of Holy Writ regarding the meaning of which we have no definite expression in the doctrinal code of the Church, we follow the _analogy of faith_; which is manifest from the general consent of the Christian Fathers and Doctors, and from the teaching of learned and holy commentators. These we may safely follow in all doubtful cases, that is to say, where there is no evidence to show that they were mistaken, either through want of certain sources of information or proofs which we have at our command presently, or because they accepted the views of their time and people, feeling that any departure from the received tradition would make disturbance, and fail of its intended good effect. It is safe to say that the conditions of one age and the modes of thought and feeling of one generation are not a just standard by which to judge the conditions and views of another age or generation. This is an important fact to remember for those who are inclined to look in every part of the Sacred Scriptures for a verification of the sentiments which they feel, and of the views and opinions of things which they hold. XVIII. RUSH-LIGHTS.