GOOD SETS OF TEETH.

Lyttelton Times, Volume LVI, Issue 6503, 30 December 1881, Page 6

GOOD SETS OF TEETH.

(Att CA« Tear Semi.) “A good set of teath and nothing to eat it a proveabial expression descriptive of a state of affairs which is universally felt to be one of some hardship. There is an incongruity between the two Ideas which is at once painful and ludicrous, and it cannot he matter for surprise that the prime object of ever;' living eraature should be to bring about a proper adjustment of a condition which, from the first moment of existence, is felt to bo intolerable. , , In many—perhaps in roost—people * minds the teeth are associated with tome of the darkect 'moments of existence j with long hoars of gnawing pain, with the tardy and unwilling visit to the dentist j above all, with that indescribable mixture ot agony and astonishment which attends the forcible elimination of the offending organs. Nevertbelese, we have thought that a brief and unteohaical description of.some of the more sinking modifications and adaptations of these organs may not be without interest to some of our reader*. The teeth of man, although they play on Important part in the production of artkukte speech, ore principally useful for the' division and mastication of tho food. In the lower animals, a gnat variety of other purposes are served by those organs. In the carnivorous tribes they are tho principal instrument# for seising and tearing the prey, and in many of tho vegetable feeder* certain of the teeth are developed into very formidable weapon* of attack or defence, a* tbe tasks of the elephant and wild boor, the powerful canine teeth of the apes, and ao on. They may be used aa an aid to locomotion, os in the esse of tbe walrus, which avails itself of its long tusks, as an assistance in climbing the rough wad broken icefield* among which Its life u passed) or they may become a means of anchorage, a purpose to which they are applied by serenu riverhaunting species. The babarootia, a speoiea of wild hog, has Its upper canine teeth modified in a most singular way to servo as a protection to the eyes, as the animal forces its way through the dense undergrowth of the tropical forests) they rise almost vertically through tbe, upper lip, and frequently curve backwards so much ae to pieroe the ahull. The beaver, with hit thorp, chisel abaped front teeth, will cut down and carry oil trees me big as a man's thigh, gnawing the wood all round, but flatting it higher on one aide, eo as to determine the direction of the fall In om>place on the banks of Urn Missouri, th* timber was completely penetrated for a distance of threekeres, and In great part removed, although, the .trees . were Tesy numerous *nd of oonniderable size. So hard is the enamel of the beaver’s tooth that, when fixed in a wooden handle, it make* a very respectable chisel, and, according to Sir John Btohardson, it is used by the Northern Indian* to eat bone, end to snap* their horntipped spears, Ao. Tbe inoisor teeth of tbe agouti, another of tbe rodents, are used in the same way by the Bratlllaa Indians to fashion tbe blow-tube* with whloh they bring down small birds and monkeys. What the little beaver doe* for building materials, tbe gigantic megathorium appears to have done for food, Thie huge extinct sloth teem* to have had for it* pleating task to uproot and tear down large forest trace for the purpose of feeding on (he branches. But although tbe secondary uses to which the teeth of various animate are applitd are many and important, their main function is undoubtedly the preparation of the food for the process of digestion and a**iautetiou. In the very lowest of animate no special dental apparatus is to be found. The food of these creature* comes to them mostly In a liquid or a very minute form, arof no special organ* are required for it* divirion and preparation i bat as soon as we begin to ascend a little in the scale, we find a number of contrivances for effecting the purpose. Organs supplying (be place of jaws, Mid armed with teeth, are found in almost all the higher invertebrates, arranged in a circle in the sea-urchin, vertical in insects, triangular in the leech, and in th* form of a long flexible ribbon in the snail. The same purpose it served by the oslearaons gentrio teeth of crabs, and to many insects, as well as certain snails, by a gtssord, or first stomach, resembling that or grain-eating bird*. The dental armament of these small deer is often surprisingly elaborate. The common sets forth to ravage our gardens equipped with one bundled and fifty rows of stout serrated teeth. The whole piste contains about twenty-one thousand teeth, while a full-grown slug has over twenty-six thousand of these silidous spikes. The whelk has a ribbon-like tongue, contained to a proboscis, with which it bores holes to the •hells of tho molluscs, whloh forms its food. Th > tongue bss strong sawUke teeth on tbe edges, with rows of finer ones between. In some moluscs the tongue resembles a tesseteted Eminent, with a tooth to the centre of each senge-sbeped compartment. But although the palatal system of the snail* forms a powerful and most efficient apparatus for triturating their food, it more closely resembles the gizzard of birds than tho teeth of quadrupeds, and it is in the class of fishes that we find tbe first example of true teeth, •ot to a bony socket, and ranged at the opening of the alimentary unal. At what lime the fashion of wearing teeth cam* in we have no means of ascertaining. If, however, lb* Darwinian theory he comet, at some enormously remote period of time some lucky animal developed tho new weapon by a series of fortunate variations, and its possession gave to him and hi* posterity snob a " puli'* over their competitors that they were able to set the fashion, which ha* lasted to the present day. The first set of teeth was probably a rude and artistic contrivance, doubtless by no means comparable with the beautiful adaptation to a special purpose, of which wa find examples to the teeth of the elephant and tiger. It has, however, been improved upon, under the p»r*»ure of llat stem necessity which make* improvement a condition of existence i and in our collection of living and fossil animats, we find teeth exhibiting every conceivable modification in number, shape, size, and mode of growth, so as to suit the varied requirements of different species, Tho number of teeth varies to a surprising manner. The lanoelet and the eiurgeon are toothless, and the tench Has hut a single grinding tooth j but roost of tbs fishes aro sxosedingly well provided in this respect, the mouths of some of them being literally studded with teeth. In many species, not only aro the jaws bristling with dosses of cornicle spikes, hut the tongue, the roof of tbe mouth, the gill-arohes, and even thebonec of the nose, aro used as prints of attachment for supplementary teeth. The wolf-fish, anarrhteai lupus, possesses a perfect dental arsenal, and the eight of his widely-opened mouth mutt he highly discomposing to any inhabitant of tbe deep not possessed of a well-grounded confidence of bis owtt iasADS of defence. The tortoises and turtles an toothless) lbs jaws of the latter, however, are covered with

tootO ipreies w«* proxldsd a £ tow mwwm»t* ars m ***£*" mtm of Brasil, and •ehldfi*} nprstentattoee of a mm teothisee fioadniped#, y*gL Stforttgr? rrv?is fSSfflSflSS^gfeS elm mammalia, bit laws one hundred to aw hundred ud nlw tosw* 1* rtdkiug mourn with tbs «Sato«*o •*«*£• meat of ths dolphin is the denial flt* l **** tiM MrtW. which cm, il item at elbow fcto tide of duplicity* The tomato •***£?*' mm lb* germs of two teedh, tmMfdiw* ia the tnbttanoe of the appsr J*w jr one of »M*» to derstoped is the wtw into t taek.from tlx to too f«t la Itafth. „,«-***, Ths toeth ptoeeftt erery wd*y ®* from th» Upy tooth of tho porch* which wo n mfemto oncl iloeely arranged ae to tor* boon com pored to plaeh or the pdo rimrg, to the hugs toil* of tho elsphtat, In *h« African elephant tho lathi aw oftoa ■!■* foot in length, and s pair of these will weigh upwards Of threw haodrod pwid»» hut inch dunsnelone wo I’M# ia th# Indian tpedss. Th« laths of ths mammoth essm to htw «*• eesded la sis* ovsa tbess toroMk wmpem, tpsefoMos haring toss toood awsscutof » lew tbsn eleven fset. Ia Ceyloa wry few of ths slsphsoto potto** laths at all, tho tow that art prorioed with them being stales ex* datively. Kearly all* bowewsr, bar# ttonted tooth ssilsd tothts* las or twelve inches ia length, cod oao or two la diameter. His modification* which mar bs otomed ia ths ships of ths tosth are dinott sadlsss, being m rsrioos as ths habits and rwplio* nsoto of ths dMsrsat spsotot. . .. Htos the whole series of tbs toslh of tho tiger Is mddfltod to form ths dsstoactirs apparatoe which hs wields with each torriao fores. The incisors, tlx ia mmber, ws short and pht«er*ehepcd, to sld la gnawing sad tosriog tbs flesh fro® ths tones. We canines, long, etrosg, sad conical, sad with soerrs iawsedf, srs ussd for ssUng sod holding ths struggling prey. Is each jaw there u a space between ths iodton axuS canines, into which lbs canines of ths op* posits jaw fit, tbslr effective slrsogth being thereby greatly inereaesd, a* they ws lbas permitted to overlap the gams when tbs month It closed. Tbs molars, or grinding teeth, intteod of being fist or greovsd, at - la herbivorous animals, are compressed and trenchant, and 'piay vertically oa sash other like a pair of editor*, so ss tooni sad coarsely diriefs ths fleeb, which is swallowed with very little mastication. The whole skali of tho tiger it so formed ss to set this torrife machinery la motion to ths most efficient ataantr, (MB'! the mtuclee which work it ars of Immense power. In •priogieg on Ibeto prey, they alwoje elm at the huge bleed* Tewclt of the »e»Jf, sad la tint way they ars enabled to orsrpower aaimsit wKab other* wiee might to aids to offsr a good reshtacea. Strong at art ths tosth of ths tiger, 'they >«• oftoaiajartd by the rlohmcs to which they are tabjectod, and In hit old age he at generally eompcllMd to seek tor prey Isas able to resist him.