Sixthly, loyalty to his teachers and leaders. From his heart he wishes to help them, and knows he can do it best with the truth. He has a grateful disposition, for he has only gained admittance through them to the high hall of science; he would never have entered by his own road. Any man to-day who can throw open a new province where his lesser disciples can work to some purpose, is famous at once; so great is the crowd that presses after him. These grateful pupils are certainly a misfortune to their teacher, as they all imitate him; his faults are exaggerated in their small persons, his virtues correspondingly diminished. Seventhly, he will follow the usual road of all the professors, where a feeling for truth springs from a lack of ideas, and the wheel once started goes on. Such natures become compilers, commentators, makers of indices and herbaria; they rummage about one special department because they have never thought there are others. Their industry has something of the monstrous stupidity of gravitation; and so they can often bring their labours to an end. Eighthly, a dread of ennui. While the true thinker desires nothing more than leisure, the professor fears it, not knowing how it is to be used. Books are his comfort; he listens to everybody's different thoughts and keeps himself amused all day. He especially chooses books with a personal relation to himself, that make him feel some emotion of like or dislike; books that have to do with himself or his position, his political, æsthetic, or even grammatical doctrines; if he have mastered even one branch of knowledge, the means to flap away the flies of ennui will not fail him. Ninthly, the motive of the bread-winner, the "cry of the empty stomach," in fact. Truth is used as a direct means of preferment, when she can be attained; or as a way to the good graces of the fountains of honour--and bread. Only, however, in the sense of the "particular truth": there is a gulf between the profitable truths that many serve, and the unprofitable truths to which only those few people devote themselves whose motto is not _ingenii largitor venter_. Tenthly, a reverence for their fellow-professors and a fear of their displeasure--a higher and rarer motive than the last, though not uncommon. All the members of the guild are jealously on guard, that the truth which means so much bread and honour and position may really be baptized in the name of its discoverer. The one pays the other reverence for the truth he has found, in order to exact the toll again if he should find one himself. The Untruth, the Error is loudly exploded, that the workers may not be too many; here and there the real truth will be exploded to let a few bold and stiff-necked errors be on show for a time; there is never a lack of "moral idiosyncrasies,"--formerly called rascalities.