This section is from the book "Human Physiology For The Use Of Elementary Schools", by Charles Alfred Lee. Also available from Amazon: Human Physiology, for the Use of Elementary Schools.
13. The sense of taste is most delicate in youth. It is much impaired by the use of alcoholic drinks, tobacco, and highly seasoned food ; so that the spirit drinker, the tobacco chewer, and the epicure often lose this sense to such a degree that they cannot relish plain dressed food. That man relishes his food best who rarely uses powerful stimulants and narcotics. Majendie says that man would probably excel all the other animals in delicacy of taste, if he did not, at an early period, impair its sensibility by strong drinks, or by the use of spices, and other luxuries.
14. The taste may be improved by cultivation like any of the other senses. Dr. Kitchener states that some epicures are able to tell from what precise part of the Thames a salmon had been caught, when presented at table. Many gourmands pretend to be able to pronounce by sipping a few drops of wine, the country whence it comes, as well as its age ; to tell by the taste, whether birds put upon the table are domesticated or wild, etc. Such acuteness of taste is however, by no means desirable, as we are liable, in the "rough and tumble" of life, to meet with so much that demands obtuseness rather than refinement of feeling. The epicure with his acuteness and delicacy of taste, is liable to continual annoyances and discomforts, while the man of simple and unsophisticated taste will receive gratification and pleasure from the very same objects which excited disgust in the former.
15. If we examine the lower animals, we shall find that in none of them is the tongue precisely like that of man. The resemblance is the nearest in apes;. but in them, even, it is much elongated. In animals that chew the cud, or ruminants, we find the tongue covered with a dense cuticle, studded over with numerous pointed papillae, especially towards the root. These projections, together with the waving ridges on their palates, are of great use in collecting and swallowing the tender herbage on which they feed. In the cat tribe, the sharp, horny prickles on the tongue, enables them to take a firm hold. In the lion and tiger these prickles are sufficient to tear off the skin even of large animals. Ant eaters are furnished with a very long and slender tongue, covered with a viscid, adhesive secretion, whereby they are able to seize their prey, on thrusting it into an ant hill.
16. Whales have an enormous tongue, though it has been doubted whether it is endowed with the sense of taste. They have, moreover, projecting downwards from the upper jaw, a kind of pallisade, consisting of several hundred plates of whalebone, the outer edges of which are sharp, the inner fringed with long hair like appendages, the spaces between the plates being little more than half an inch. The length of the plates sometimes exceeds twelve feet. This pallisade, when the mouth is closed, is covered by the enormous fleshy lower lip, but when open, it presents a kind of grating through which the water loaded with medusa and other small animals, flows. Captain Parry states that these medusa or sea blubber, so abound in the arctic seas, that when the water is still, and the surface smooth, they present a striking resemblance to a thick snow fall, when the flakes are large and the air calm. The soft, spongy texture which forms the tongue of the whale, is thought to be better adapted for licking the food from the hairy whale bone roof, and transferring it to the gullet, than to serve as an instrument of taste.
17. The tongue of birds varies much in form and consistence. In some, it is horny, as in the toucan, where it is several inches in length and exceedingly narrow, like a long strip of whale bone; or in the wood pecker, to the tip of whose tongue there is fixed a long, sharp, pointed, spear like body with serrated edges, for piercing and seizing on insects burrowing beneath the bark of trees. Parrots, which belong to the same class, have soft fleshy tongues well adapted to the exercise of taste.
28. In reptiles also, we find great variety of forms and applications of the tongue. In the crocodile it is small and immoveable, so much so, as to lead some naturalists to deny its existence. In serpents, it is forked, and susceptible of considerable motion; while in the frog, it is folded back in the state of inactivity ; but when the animal is about to seize an insect, it suddenly unfolds and projects it out of the mouth. The tongue of a chameleon is contained within a sheath, and admits of being projected to the extent of six inches, and is besmeared with a glutinous secretion. In the twinkling of an eye it is darted out to catch its food, which consists chiefly of flies. Fishes have the mere rudiments of a tongue, fixed near the throat, which is often furnished with teeth. There is reason to believe that many of the inverte brated animals are endowed with taste, such as bees, wasps, flies, and leeches.
To what sense is that of taste allied ? What is sapidity ? What is the chief organ of taste ? What other parts participate in the function? Describe the structure of the tongue. From what source does the tongue derive its nerves ? Which is the nerve of taste ? What are papillae ? How many kinds are there on the tongue ? What is the office of the mucous papillae ?-Of the conical and fungiform ? What is the process of taste ? Can insoluble substances be tasted ? Why not ? What are the use of the salts in the saliva ? How do we taste metals ? How is the taste excited by galvanism explained ? Are there many savours ? Name some. Can they be classified ? Why not ? What articles leave a taste in the mouth the longest ? What use can be made of this fact ? How do tasters manage ? Is taste under the influence of habit ? What facts show this ? To what is the pleasure of eating owing ? How is this shown ? Is the taste a sure guide to what is safe and nutritious ? Do animals differ as to taste ? Do they possess it in as great perfection as man ? Does it ever become morbid in them ? When is taste most delicate? How is it impaired? May the taste be improved? Are the advantages or disadvantages the greatest, which attend great delicacy of taste ? Have any of the lower animals a tongue like that of man? Describe some peculiarities? What apparatus have whales for eating small sea animals ? What is said of the tongue of birds ?- of reptiles ? of fishes ? Do any of the invertebrated animals possess the faculty of taste ?