"In what consists the principal and most characteristic difference between one human intellect and another? In their ability to judge correctly of evidence. Our direct perceptions of truth are so limited; we know so few things by immediate intuition, or, as it used to be called, by simple apprehension-that we depend for almost all our valuable knowledge, on evidence external to itself; and most of us are very unsafe hands at estimating evidence, where an appeal cannot be made to actual eyesight. The intellectual part of our education has nothing more important to do than to correct or mitigate this almost universal infirmity-this summary and substance of nearly all purely intellectual weakness. To do this with effect needs all the resources which the most perfect system of intellectual training can command. Those resources, as every teacher knows, are but of three kinds: first, models; secondly, rules; thirdly, appropriate practice. The models of the art of estimating evidence are furnished by science; the rules are suggested by science; and the study of science is the most fundamental portion of the practice. The logical value of experimental science is comparatively a new subject, yet there is no intellectual discipline more important than that which the experimental sciences afford. Their whole occupation consists in doing well, what all of us, during the whole of life, are engaged in doing, for the most part badly. All men do not affect to be reasoners, but all profess, and really attempt, to draw inferences from experience: yet hardly any one, who has not been a student of the physical sciences, sets out with any just idea of what the process of interpreting experience really is. If a fact has occurred once or oftener, and another fact has followed it, people think they have got an experiment, and are well on the road toward showing that the one fact is the cause of the other. If they did but know the immense amount of precaution necessary to a scientific experiment; with what sedulous care. the accompanying circumstances are contrived and varied, so as to exclude every agency but that which is the subject of the experiment-or, when disturbing agencies can

not be excluded, the minute accuracy with which their influence is calculated and allowed for, in order that the residue may contain nothing but what is due to the one agency under examination; if these things were attended to, people would be much less easily satisfied that their opinions have the evidence of experience; many popular notions and generalizations which are in all mouths, would be thought a great deal less certain than they are supposed to be; but we should begin to lay the foundation of really experimental knowledge, on things which are now the subjects of mere vague discussion, where one side finds as much to say and says it as confidently as another, and each person's opinion is less determined by evidence than by his accidental interest or prepossession. In politics, for instance, it is evident to whoever comes to the study from that of the experimental sciences, that no political conclusions of any value for practice can be arrived at by direct. experience. Such specific experience as we can have, serves only to verify, and even that insufficiently, the conclusions of reasoning. Take any active force you please in politics, take the liberties of England, or free trade; how should we know that either of these things conduced to prosperity, if we could discern no tendency in the things themselves to produce it? If we had only the evidence of what is called our experience, such prosperity as we enjoy might be owing to a hundred other causes, and might have been obstructed, not promoted, by these. All true political science is, in one sense of the phrase, a priori, being deduced from the tendencies of things, tendencies known either through our general experience of human. nature, or as the result of an analysis of the course of history, considered as a progressive evolution. It requires, therefore, the union of induction and deduction, and the mind that is equal to it must have been well disciplined in both. But familiarity with scientific experiment at least does the useful service of inspiring a wholesome skepticism about the conclusions which the mere surface of experience suggests."

The discipline of observation and strict reasoning afforded by the exact sciences, mathematics, physics, and chemistry, pure and applied, being secured, we then pass to the study of the biological sciences, botany, zoology, physiology, geology. A new order of truths and new circumstances of knowledge are here encountered, to which the sciences just considered are an indispensable introduction, but for which, the mental habits they form are not an adequate preparation. We are still carefully to observe, still to reason from facts to general principles, but the facts, though equally positive, are now so different-so complex, inaccessible, and indefinite, as to embarrass inference, and call for a higher exercise of the judgment. Experiment or active observation, which plays so prominent a part in physics and chemistry, is here greatly limited; we cannot isolate the phenomena, and turn them round and round, and inside out, so as to compel a revelation of their secrets: hence, in proportion as the sources of error become more numerous and fallacies more insidious, a subtler exercise of the reason is demanded-more circumspection in weighing evidence and checking conclusions, and a severer necessity for suspension of judgment. As the biological sciences deal with the laws of life and the phenomena of living beings, man in his animal constitution and relations, is included in their subject-matter, while the problems presented exercise the mind in a manner similar to the formation of judgments upon human affairs. Complete or demonstrative induction being impossible, we are compelled to form conclusions from only a part of the facts involved, and to anticipate the agreement of the rest. This is reasoning from analogy, a powerful but perilous mode of proceeding; one which we are compelled constantly to adopt in our mental treatment of the concerns

of life, and for which biological studies are eminently suited to give the requisite discipline.

Another advantage of the study of these subjects is afforded by the comprehensiveness and perfection of their classifications. No other subjects compare with zoology and botany in these respects. Not only do they furnish inexhaustible material for the exercise of memory, but by the presentation of facts in their natural relations, they exercise it in its highest and most perfect form. It is maintained by Agassiz that classifications in natural history are but reports of the order of Nature-expressions of her profoundest plan; and he even goes so far as to interpret them as a divine ideal programme of constructions, of which the living world is but the execution. However this may be, it is certain that they open to us the broadest view of the relations and harmonies of organic nature, and are best fitted to discipline the mind in dealing with large co-ordinations, and the comprehensive arrangement of objects of thought, whether in the arts, the professions, business, or science. But here, again, I may say, it is unnecessary to expatiate upon advantages which the reader will find more fully and lucidly treated by Professors Henfrey, Huxley, and Paget, in the body of the present work.

Dr. Whewell, in his defence of the absorbing attention given to mathematics and physics, in the University of Cambridge, has urged the necessity of admitting, as means of education, only those subjects, the truths of which are demonstrated and settled forever. But what is the extent of the field of the absolutely unquestionable? Mathematics do indeed present truths upon which rational beings can never disagree; but supposing that the student becomes a little inquisitive, and ventures to ask something about the grounds and origin of these truths, he is in

stantly launched into the arena of polemical strife, and his teacher, from being a frigid expositor of self-evident principles, is suddenly transformed into an ardent partisan. Dr. Whewell has been the life-long champion of certain views respecting the nature of mathematical conceptions, which are sharply contested, and have certainly no more than held their own in philosophical conflict. In the field of physics, also, has not the present generation witnessed one of the deepest and most comprehensive revolutions which the history of science records-the acceptance of a totally new view of the nature and relations of forces? What, indeed, is the object of education, the leading out of the mind, if not to arouse thought and provoke inquiry, as well as to direct them? Is the student's mind a tank to be filled, or an organism to be quickened? It may be well-pleasing to indolent and arrogant pedagogues never to have their assertions questioned, but it is wholesome neither for themselves nor their students.

Important as may be the mental preparation for dealing with certainties, it is still more important to prepare for dealing with uncertainties: to ignore this, arrests education at an inferior stage, and but ill prepares for the emergencies of practical life. It is matter of notoriety that the socalled liberal culture is no adequate protection against numerous fallacies and impostures which are current in society; and to so great an extent is this true that it is common to question whether, after all, for our real needs, education is better than ignorance. But there is an educated ignorance,' which, for the great end of guiding to action. and ruling the conduct, is as worthless as blank ignorance. Take the charlatanries of medical treatment; take the question of so-called 'spiritual manifestations,' and we find persons of reputed culture and good sense venturing opin