If there is any truth in the above, it follows that our conception of the words "science" and "scientific" must undergo some modification. Not that we should speak slightingly of science, but that we should recognise more than we do, that there are two distinct classes of scientific people, corresponding not inaptly with the two main parties into which the political world is divided. The one class is deeply versed in those sciences which have already become the common property of mankind; enjoying, enforcing, perpetuating, and engraining still more deeply into the mind of man acquisitions already approved by common experience, but somewhat careless about extension of empire, or at any rate disinclined, for the most part, to active effort on their own part for the sake of such extension--neither progressive, in fact, nor aggressive--but quiet, peaceable people, who wish to live and let live, as their fathers before them; while the other class is chiefly intent upon pushing forward the boundaries of science, and is comparatively indifferent to what is known already save in so far as necessary for purposes of extension. These last are called pioneers of science, and to them alone is the title "scientific" commonly accorded; but pioneers, important to an army as they are, are still not the army itself, which can get on better without the pioneers than the pioneers without the army. Surely the class which knows thoroughly well what it knows, and which adjudicates upon the value of the discoveries made by the pioneers--surely this class has as good a right or better to be called scientific than the pioneers themselves. These two classes above described blend into one another with every shade of gradation. Some are admirably proficient in the well-known sciences--that is to say, they have good health, good looks, good temper, common sense, and energy, and they hold all these good things in such perfection as to be altogether without introspection--to be not under the law, but so entirely under grace that every one who sees them likes them. But such may, and perhaps more commonly will, have very little inclination to extend the boundaries of human knowledge; their aim is in another direction altogether. Of the pioneers, on the other hand, some are agreeable people, well versed in the older sciences, though still more eminent as pioneers, while others, whose services in this last capacity have been of inestimable value, are noticeably ignorant of the sciences which have already become current with the larger part of mankind--in other words, they are ugly, rude, and disagreeable people, very progressive, it may be, but very aggressive to boot.