any kind of food distasteful, and some kinds absolutely nauseous. In every point of view, this feeling is as much dependent on the condition of the alimentary canal as on the material tasted.

The different degrees of relish and nausea exhaust all that part of taste in sympathy with digestion; what follows, next in order, belongs (II.) to the distinctive sensibility of the tongue.

9. Sweet tastes. At the head of these, we must class the sugary taste, as being the most prevalent of all forms of sweetness. The sweetness of every kind of fruit, of bread, of milk, of alcoholic liquors, and of confectionery in general, is known to arise from sugar. Besides the relish, it acts strongly upon the sense of taste proper; but no pleasure of mere taste can be compared in amount and influence to an agreeable alimentary feeling. We can lay it down as a rule, that the pleasures of taste proper have as a whole a less influential action than the other class, and this must serve as a defining circumstance for every individual of them. The feeling of a sweet taste is acute, but does not inspire the energy of volition that follows up a savoury morsel. When digestion is satisfied, there remains the enjoyment of sweets, and when the taste for these becomes cloyed by repetition, it is by an independent effect on the gustatory nerves.

But the great distinction of this feeling, and of all other feelings of taste proper, relates to the intellect, or to the power of discrimination belonging to this organ, whereby au indefinite number of substances can produce impressions recognized by us as totally different in character, which impressions of difference can remain or be recalled, after the original is gone, to compare with new cases that may arise, and to give that sense of agreement or disagreement whereou all our knowledge of the world is based. In the case of sweetness, for example, not only can we be affected with the pleasurable feeling or emotion belonging to it, but we can be distinctively affected by a great many substances possessing the quality; we can identify some, and feel a want of identity

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in others; and we can so far retain the impression of a taste of yesterday as to compare it with a taste of to-day. This feature distinguishes the feelings of the mouth from organic feelings; it distinguishes in some degree tastes from relishes, although these last are also discriminated to a considerable extent; and it is the point of superiority which sight, hearing, and touch, have to a still greater degree over organic sensations.

These are exemplified by quinine,

10. Bitter tastes. gentian, or bitter aloes. This, and not sourness, is the proper contrast of sweet. As sweetness is the pleasure proper to taste, so bitterness is the peculiar or distinctive form of pain inflicted through this sense. Without having the bulk and influence of the massive forms of pain, this sensation is highly intense in its own limited region, expressing itself by wryness and contortion of the features. The sweet and the bitter represent the two characteristic modes of acting on the pure gustatory nerves. They are distinct from relish on the one hand, which involves sympathies with the stomach, and from the modes of tactile sensibility on the other. The classes that remain involve (III.) in a greater or a less degree the nerves of touch.

11. Saline tastes. Common salt may be taken as an example of this class. Mineral waters, containing salts of soda, magnesia, and lime, have a saline taste. This taste is rarely an agreeable one, in many cases it is very disagreeable, but we should be disposed to describe the feeling, in most instances, as singular and characteristic rather than as either pleasing or the reverse. Of it, as of all that follow, the character is best expressed by saying, that it can be discriminated from every other.

The repulsive taste of Epsom salts would be termed a compound of the saline and the bitter.

12. The alkaline taste is usually more energetic than the saline, as might be expected, seeing that a salt is a neutralized alkali. But if the remark above made be correct, namely, that salts owe their taste principally to their base, the alkali

ought to have a considerable share of the saline in taste. Most mineral alkalies, and some earths and oxides of metals have characteristic tastes, rarely agreeable, and often not markedly disagreeable.

13. The sour or acid taste is much more uniform in its nature than either the saline or the alkaline; which we may fairly ascribe to the influence of the acid quality itself, irrespective of the constituent elements. This is a sharp, penetrating, pungent action, having, when very powerful, the pain more of a burn, than of a repulsive taste; in diluted forms it is an agreeable pungent stimulus to the mouth; hence the liking for vinegar (the sour of cookery as sugar is the sweet), and for acid fruits and vegetables. A galvanic current in the mouth causes sourness.

14. The astringent is a distinct form of the sensation of taste; as an example we may refer to the effect of alum in the mouth. It is evident, however, that in the acid action, and still more in this of astringency, we depart farther and farther from the proper feeling of taste. Astringent substances act on the skin and on the mucous membranes generally; and the influence lies in a kind of contraction or forcible shrinking of the part, to which we are sensitive whenever it occurs as a touch. The 'rough taste of tannin' may be put down under astringency.

15. The fiery taste of alcoholic liquors, mustard, pepper, camphors, and volatile oils, given in Gmelin's classification, seems to me to be happily designated. I am inclined to think that this too is more a tactile action than a gustative, although in some of the other substances entering with alcohol into wines, spirits, and malt liquors, there is a genuine stimulus of the taste. The acrid taste may be looked on as a form of the fiery, or astringent, combined with some ingredient of the bitter. On the other hand, the effect of peppermint resembles a cold contact on the skin. The pungency that marks all this class of sensations is a remarkable state of feeling, deserving to be once for all discussed at length. This discussion, however, I prefer to take

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up under the sense of smell, the next in order in our arrangement.

16. With regard to the Intellectual aspect of Tastes in general, Longet observes that these sensations are deficient as regards the power of being remembered; and he gives as a proof the fact that, when we dream of being present at a repast, we see the viands but do not taste them. The fact is not beyond question, and besides, it is an extreme comparison; it contrasts the most intellectual of all the senses, the most abiding of all sensations, with those that are least so. It is so far true, that we do not recover sensations of taste so as to live habitually on the ideas of them, but they are slightly recoverable even as ideas, and for the purposes of identification and contrast, they may be recovered to a very great extent. A wine tasted to-day can be pronounced the same or not the same as a wine tasted a week ago, while well marked tastes may be remembered for years in this way.

The intellectual character of the sense is also illustrated by its improvability. A wine-taster, a cook, or a chemist, can acquire a delicate sensibility to differences of taste, implying that its impressions can find an abiding place in the memory.

SENSE OF SMELL.

This sense is in close proximity to the organ of Taste, with which smell frequently co-operates; but we may consider it as placed at the entrance of the lungs to test the purity of the air we breathe.

1. The external objects of Smell, the material substances whose contact produces the sensations, are very numerous. They require to be in the gaseous state, in the same way that the objects of taste require to be liquified. Solids and liquids, therefore, have no smell except by being evaporated or volatilized.

The greater number of gases and vapours are odorous. Of inodorous gases, the principal are the elements of the

atmosphere, that is to say, nitrogen, oxygen, vapour of water or steam, and carbonic acid. In the long list of gaseous bodies recognized by the chemist, we find very generally some action on the nostrils,-carbonic oxide, sulphurous acid, chlorine, iodine, the nitrous gases, ammonia, sulphuretted and phosphoretted hydrogen, &c., the vapour of muriatic, nitric, and other acids. The singular substance ozone, produced occasionally in the atmosphere, is named from its smell, which is the smell of sulphur, and of the odour given forth by electricity. Some of the metals and solid minerals give out an odour, as, for example, the garlic smell of arsenic, and the odour of a piece of quartz when broken. The effluvia of the vegetable kingdom are countless; besides such widely spread products as alcohol and the ethers, a vast number of plants have characteristic odours, usually attaching to their flowers. The animal kingdom also furnishes a variety of odours; some general, as the 'scent of blood,' and others special, as musk, the flavour of the cow, the sheep, the pig. All volatile organic compounds,' says Gmelin, 'are odoriferous, and most of them are distinguished by very strong odours; e.g. volatile acids, volatile oils, camphors or stearoptenes, and alcoholic liquids; marsh gas (carburetted hydrogen), and olefiant gas, have but very little odour.'

The pleasant odours, chemically considered, are hydrocarbons; that is, they are composed chiefly of hydrogen and carbon. Such is alcohol and the ethers, eau de Cologne, attar of roses, and the perfumes. Many smells, however, elude investigation from the minuteness of the substance causing them. Thus the vinous flavour is due to a substance which the chemist has been able to separate, being termed the œnanthic ether; but the bouquet of individual wines has not been laid hold of.

With regard to carbonic acid, the assertion as to the absence of smell is true of the amount present in the atmosphere: but, collected in mass, this gas has a slightly pungent, somewhat acid odour. As with pungent odours generally, the effect is probably due to the irritation of the nerves of the filth pair, and not to the proper olfactory sensibility.