how can I determine whether the pictures are likenesses or are mere productions of the fancy, if neither I nor any other man had ever seen any originals of which they could be the resemblances? Hence it is manifest that the evidence of the existence of a material world, or of anything existing out of the mind, is at once swept away. Reasoning in this manner, Bishop Berkeley arrived at idealism. He denied the existence of an external world, and concluded that nothing existed but spirit and the affections of spirit.

But this idea was generalized. It was admitted that we could not cognize external objects directly, but only through the medium of representative images. If this is true of material, why is it not true of spiritual objects,— of the cognitions of consciousness? Why do we not cognize them by means of representations? But if we cognize them thus, and have no cognition of the objects themselves, how do we know that there is any such existence as mind or its faculties? In short, how do we know that anything exists but ideas and impressions? How do we know that any such realities exist as time, space, eternity, Deity? All is resolved into a succession of ideas, which follow each other by the laws of association, and besides these there is nothing in the universe. This is nihilism, and such consequences were actually deduced by some philosophers from this doctrine. It was surely important to examine the evidences of an hypothesis which led to such results.

This imperfect fragment of the history of intellectual philosophy is not without its value. It teaches us the vast superiority of the acknowledgment of ignorance, to the gratuitous assumption of knowledge. When we have reached the limits of our knowledge, there is no harm in confessing that beyond this we do not know. But to look out into the darkness, and dogmatically affirm what exists beyond the reach of our vision, may exclude invaluable truth, and in

troduce the most alarming error. Thus, in the present in stance, a hypothetical explanation of a fact, which in our present state does not seem to admit of explanation, when carried out to its legitimate results was found to terminate in universal scepticism, and furnish a foundation for consistent atheism. Philosophy will certainly have made important progress when it shall have been able accurately to determine the limits of human inquiry.

REFERENCES.

Representative images - Locke, Book 2, chap. 3, sec. 1; chap. 8, sec. 12; chap. 11, sec. 17. Reid's Inquiry, chap. 1, secs. 3-7; 2d Essay, chaps. 4, 7, 9, 14. Stewart, vol. 1, chap. 1, sec. 3. Introduction, Part 1, vol. 2, chap. 4, sec. 1; chap. 1, sec. 3. Cousin, Psychology, chaps. 6 and 7.

Knowledge an agreement between the idea and object chap. 1, sec. 2; chap. 4, sec. 3.

Cousin, chap. 6.

Locke, Book 4,

Three things existent in perception — Reid, 2d Essay, chap. 5.

Idealism and Nihilism— Cousin, chap. 6, last part, and chap. 7 Reid 2d Essay, chaps. 10-12.

8, sec Essay, n, Part chaps. 6

Book 4,

Beid

SECTION IV. OF THE SENSE OF SMELL.

HAVING, in the preceding chapter, treated of our perceptive powers in general, I proceed to describe the particular senses with which we have been endowed. Proceeding from the simpler to the more complex, I shall examine, in order, smell, taste, hearing, touch and sight.

The organ of smell is situated in the back part of the
nostrils. It is composed of thin lamina of bone, folded
together like a slip of parchment, over which the olfactory
nerve is spread, covered by the ordinary mucous membrane
which lines the mouth and posterior fauces. It is so situ-
ated that the whole surface of the organ is exposed to the
current of air in the act of inspiration.

In those animals which seek their prey by scent, this or-
gan is found larger, exposing a greater amount of surface
to the air, than in those which pursue their prey by sight.
The perfection in which this sense is enjoyed by some of the
lower animals has always been a subject of remark.
dog will track the footsteps of his master through the streets
of a crowded city, and, after a long absence, will recognize
him by smell as readily as by sight or hearing.

A

When we are brought near to an odoriferous body, we immediately become sensible of a knowledge, a feeling, or a

particular state of mind. If a tuberose is brought near a person who has never smelled it, he is at once conscious of a form of knowledge entirely new to him. If we do not by our other senses, know the cause of the sensation, we have no name for it, but are obliged to designate it by referring to the place where we experienced it. If, by our other senses, we have learned the cause of the sensation, we designate it by the name of the object which produces it. Were the perfume of a rose present to me for the first time, and did I not see the flower, I could give to it no name. As soon as I have ascertained that the perfume proceeds from the rose, I call it the smell of a rose. We thus seo

clearly that from this sense we derive nothing but a sensation, a simple knowledge, which neither gives us a cognition of anything external, nor teaches us that anything exists out of ourselves.

The exercise of this sensation is either agreeable, indifferent or disagreeable. The perfume of flowers, fruit, aromatic herbs, &c., is commonly pleasant. The odor of ob jects in common use is generally indifferent. The odor of putrid matter, either animal or vegetable, is excessively disagreeable. In general, it may be remarked that substances which are healthful for food are agreeable to the smell; while those which are deleterious are unpleasant. The final cause of this general law is evident, and the reason why the organ of smell in all animals is placed directly over the mouth. Odors of all kinds, however, if they be long continued, lose their power of affecting us. We soon

become insensible to the perfume of the flowers of a garden; and men, whose avocation requires them to labor in the midst of carrion, after a short time become insensible to the offen sive effluvia by which they are surrounded.

Pleasant odors are refreshing and invigorating, and restore, for the time, the exhausted nervous energy. Offen

sive odors, on the other hand, are depressing to the spirits, and tend to gloom and despondency. The former of these effects is alluded to with great beauty in the well-known lines of Milton

"As when to them who sail

Beyond the Cape of Hope, and now are past
Mozambique; off at sea, north-east winds blow
Sabean odors from the spicy shore

Of Araby the blest; with such delay

Well pleased, they slack their course, and many a league,
Cheered with the grateful smell, old Ocean smiles."

Paradise Lost, Book 4, lines 159-165.

Concerning the manner in which this sensation is produced, I believe that but one hypothesis has been suggested. The received opinion is that what is called effluvia, or extremely minute particles, are given off by the odorous body, that these are dissolved in the air, and brought in contact with the organ of this sense in the act of breathing. That this may be so is quite probable. It is, however, destitute of direct proof, and is liable to many objections. It is dif ficult to conceive how a single grain of musk can, for a long time, fill the area of a large room with ever so minute particles, without visible diminution of either volume or weight. Until, however, some better theory shall be presented, we seem justified in receiving that which even imperfectly accounts for the facts in the case. Still, we are to remember that it is merely a hypothesis, to be abandoned as soon as any better explanation is established by observation.

From what has been already remarked, it must be, I think, evident that the sense of smell gives us no perception. It is the source of a simple knowledge which alone would never lead us out of ourselves. This sensation clearly gives us no notion whatever of the quality which produces