along this channel to the mind a perfectly pleasurable stimulus. The sweetness may accompany freshness or it may not. The odour of the violet is a pure instance; the rose, jasmine, orange, lemon, lavender, rosemary, are well known examples of odorous plants. The cases of sweetness enjoyed with some other quality are also extremely numerous. Sweetness is a name for a variety of pleasures. Derived originally from taste, it is extended to smells, to sounds, and to several of the higher emotions, such as the tender affections, and the beautiful in nature and in art. These feelings are so far of a kindred nature, as to suggest and support each other. They all agree in being forms of pure passive pleasure. In this respect, they resemble muscular repose, warmth, and healthy digestion; but they are more acute than these states; they are also more intellectual, as shown both in discrimination and in ideal persistence, which gives the superiority indicated by the name 'refinement.' 11. The opposite of sweet in odours is described by the general name stinks; the expressive word bitter is not usually applied to smell. The term 'mal-odour' has been proposed, and would be a convenient word. If we leave out both the nauseous odours, and certain other forms of the disagreeable to be afterwards described, this class will be limited considerably. Assafoetida may be given as an example of an odour intensely repulsive by its action on the olfactory nerves alone. The cadaverous odour is of the repulsive kind, but it is only one of many forms of disagreeable effluvia arising from animal decay. The aroma of some plants, as those quoted by Linnæus, has an intensely unpleasant action. The disagreeable marsh smell may be experienced in its strongest form by squeezing in the fingers the brown scum of a stagnant pond, and applying them to the nose. The varieties of bad odours are endless. As sweetness is the proper pleasure of smell, the effect of a stink is the proper pain of the organ,-the influence originating the peculiar form of misery that we are adapted to receive by means of this sense. The sensation may be speci fied as the nose-pain. Of an intense, rather than a massive character, we are stunned and discomposed, but not necessarily depressed or prostrated by it. It resembles in this respect a bitter taste, and is contrasted with the massive pains of chillness, indigestion, or disgust. The expression is in accordance with the acuteness of the sensation, being an intense contortion of the features, chiefly about the nose. A sort of hysteric smile may likewise be provoked. The peculiar feeling of an ill smell is often appealed to metaphorically, to express the feelings caused by human conduct. 12. The name pungent is applicable to a large class of odours, and the quality enters as an ingredient into many more. Ammonia is the type of substances producing this sensation. Nicotine, the snuff odour, is the best known example, a substance having a chemical analogy to ammonia. Pepper, mustard, and many of the acid effluvia have a pungent action. This effect, however, is not an olfactory effect in the proper sense of the word; like astringency and acidity in taste, it would probably arise through the nose independently of the power of smell. Snuff-takers are often devoid of smell; they lose the sense of sweet or repulsive in odours properly so called, but are still susceptible of the nicotine pungency. The influence flows through the same channel to the brain, and is of the same nature, as pricking the nose, or pulling out hairs, being conveyed by the nerves of common sensation. The excitement of pungency is a characteristic variety of the human consciousness, a species of agreeable sensation interesting to study. It shows the effect of a sharp mechanical irritation of the nerves that does not amount to acute pain. A scratch, or a blow on the skin, an electric spark, a loud crash, a brilliant flame, a scorching heat, are all pungent effects, and seem to operate as causes of excitement. They rouse the system from ennui; they are a species of intoxication. They exalt, for the time being, the tone of the mind. They come therefore to be one of the cravings associated with ennui, or depression of mind; they are like wise a stimulus for bringing out the exuberance of the animal spirits in the young and vigorous. 13. The ethereal is a distinct variety of the sensations of smell, and is probably a mixture of pungency with odour strictly so-called. Alcohol and the ethers, including chloroform and the substance first employed as an anesthetic, will recall this effect. There can be no question but that alcohol and the vinous aromas have true odours; most probably, however, they have an influence upon other nerves than the olfactory; just as the fiery taste attributed to them is something beyond the gustatory feeling. At all events the odour is distinct. It is not destitute of sweetness, but something besides sweet is wanted to express it. The sulphurous and electrical odour, which is also the odour of ozone, may be referred to the same class. If we were to recognize a class of acrid odours, they would only be a mixture of pungency and bad smell; like many of the so-called empyreumatic odours resulting from the action of heat on vegetable bodies, as in the manufacture of coal gas. 14. The appetizing smells might be treated as a class apart from the rest. The smell of flesh excites the carnivorous appetite, and rouses the animal to pursuit. We may probably consider this influence as similar in its working to the first taste of savoury food; by the law of feeling-prompted movement, it sets on the activity for an increase of the gratification. A savoury smell may partly give a commencing pleasure of digestion, and partly stimulate the appetite. The sexual excitement in some animals is induced by smell. Sympathy and antipathy are alike generated by odours. The influence of odours upon the voluptuous tender emotions has not escaped the notice of the poets. Cabanis observes that the odours of young animals are of a kind to attract, and, he considers, even to invigorate, the older. 15. Tastes, properly so called, affect only the gustatory nerves, and are therefore the same whether the nostrils are opened or closed. But many sapid bodies are also odorous. In the act of expiration accompanying mastication, especially the instant after deglutition, the odorous particles are carried into the cavities of the nose, and affect the sense of smell, or make their odour apparent. This effect is what we term flavour. Some bodies, as cinnamon, have hardly any taste, but a flavour, in other words an odour, brought out by masti cation. 16. Smell, like taste, is an important instrument in the discrimination of material bodies, and therefore serves a high function in guiding our actions and in extending our knowledge of the world. Man does not exemplify the highest development of this organ. The order of ruminants, certain of the pachydermatous animals, and above all the carnivorous quadrupeds, excel the human subject in the expansion given to the membrane of the nose, and in a corresponding sensibility to odours. The scent of the dog is to us almost miraculous; it directs his pursuit, and tells him his whereabouts. It may act the part of sight in enabling him to retrace his steps or to find out his master. SENSE OF TOUCH. 1. Physiologists, in describing the senses, usually commence with Touch. This,' say Messrs. Todd and Bowman, is the simplest and most rudimentary of all the special senses, and may be considered as an exalted form of common sensation, from which it rises, by imperceptible gradations, to its state of highest development in some particular parts. It has its seat in the whole of the skin, and in certain mucous membranes, as that of the mouth, and is therefore the sense most generally diffused over the body. It is also that which exists most extensively in the animal kingdom; being, probably, never absent in any species. It is, besides, the earliest called into operation, and the least complicated in its impressions and mechanism.' It may be well admitted that Touch is less complicated than Taste, in whose organ four different kinds of sen sations may be said to meet, the tactile being one of them. It may be further said of touch, that the mode of action (mechanical contact or pressure), appears to us the most simple of any. Nevertheless, Touch is an intellectual sense of a far higher order than these. It is not merely a knowledge-giving sense, as they all are, but a source of ideas and conceptions of the kind that remain in the intellect and embrace the outer world. The notions of the size, shape, direction, distances, and situation of external bodies may be acquired by touch, but not by either taste or smell. But this last assertion must be accompanied by an important explanation. Touch, considered as a source of ideas such as those, is really not a simple sense, but a compound of sense and motion; and it is to the muscular part of the sense, or to the movements of the touching organs, that these conceptions owe their origin and their embodiment, as we have endeavoured to show in the previous chapter. The superiority of touch to taste and smell, in this view, therefore, consists in its union with movement and muscular sensibility; and the same advantage pertains to sight. The contact of solid bodies with the surface of the body gives occasion to the exercise of movement, force, and resistance, and to the feelings and perceptions consequent on these: which cannot be said to any extent of smell, nor of taste properly so-called. A second feature marking the superiority of the sense of Touch, and qualifying it to furnish intellectual forms and imagery, is the distinctness or separateness of the sensations felt over the different parts of the skin. The sensations of the different parts of the surface of smell, would seem all to fuse into one stream of sensibility; it is not possible ever to refer a smell to any one portion of the membrane more than another. But the sensations of the skin are conveyed by distinct nervous filaments; each little area of skin has a separate nerve, and an independent communication with the nerve centres, whereby we can, after a little education, refer each sensation to the spot where the contact is made. The |