These and similar congenital differences in men's intellectual constitutions might be illustrated indefinitely if it were necessary. A further remark of Bacon's must, however, be quoted, for it goes deeper in mental analysis and touches a less obvious point. "There is one principal and, as it were, radical distinction between different minds in respect of philosophy and the sciences, which is this: that some minds are stronger and apter to mark the differences of things, others to mark their resemblances. The steady and acute mind can fix its contemplations and dwell and fasten on the subtlest distinctions; the lofty and discursive mind recognizes and puts together the finest and most general resemblances." Men belonging to the former class we should call logical and critical; those belonging to the latter, imaginative and constructive. Each class tends to the excesses of its own predominant powers, and in each case excess interferes with calm reasoning and sound judgment. To correct the personal equation it is imperative that we should study ourselves conscientiously, consider dispassionately the natural tendencies of our birth, early surroundings, education, associations, and interests, and do our utmost to conquer, or at least to make allowance for, every individual peculiarity, temperamental or acquired, likely to turn the mind aside from the straight line of thought. Such self-discipline every one must strenuously undertake on his own account if he would wish to see things as they really are. Stated in more general terms, our aim must be to rise above all kinds of provincialism and personal prejudice, and to overcome our natural proneness to rest content in our own particular point of view. Bacon quotes with approval the words of Heraclitus: "Men look for sciences in their own lesser worlds, and not in the greater or common world." We must strive to escape from our own lesser world, and to make ourselves citizens of the greater, common world. For this we need the widest and most generous culture--the culture that is to be found in books, in travel, in intercourse with men of all classes and every shade of opinion. Left to ourselves we only too sedulously cultivate our own insularity; we mingle simply with the people who agree with us, belong to our own caste, and share our own prejudices; we read only the papers of our own party, the literature of our own sect; we allow our own special interests in life to absorb our energies, color all our thoughts, and narrow our horizon. In this way the Phantoms of the Cave secure daily and yearly more despotic sway over our minds. Self-detachment, disinterestedness, the power of provisional sympathy with alien modes of thought and feeling, must be our ideal. "Let every student of Nature," says Bacon, "take this as a rule, that whatever his mind seizes and dwells on with particular satisfaction is to be held in suspicion, and that so much the more care is to be taken in