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of the body, and from the middle to the tail they grow ltffs and left again ; and all in lhape much referable the broad and flat feeds of the common garden parfhip. There is fome variety in the colours of this creature, whether accord- ing to the difference of age or fex, or from letter accidents. The moft ufual colours are thefe : the fcalcs are of a dufky greeniih, like the feathers of the back of the green-finch, and are variegated with fmall black fpots in great number ; there alfo are four large ones of the fame colour. Ra/s Syn. An. p. 291. ^/f«'sNat. Crotaph. The back is of a mixt colour, of a dead yellowim brown, variegated with blotches of black and yellow, and with a number of fmall dots of the fame colours ; the larger blotches being kid in great regularity, and making a very beautiful 'teflelatcd figure ; the fcalcs become darker as they approach the tail, where they arc almoft black; and thofe on the ridge of the back, all along, are raifed into a fort offharp prominence in their middle, like the fcales of a crocodile; thofe on the fides are plain and flat- The belly is all along covered with oblong paraHeUogram fcales, laid tranfverfely • thefe are very bright and glofly, and are yellow, fpotted with black.
The head is fmall, in proportion to the body, but the mouth is capable of opening to a prodigious width. The tongue is wholly like that of the viper, compofed of two oblong portions, joined toward the bafes, but feparate as they approach the end. The teeth are of two kinds, the fmaller ones defigned for its eating with, the larger and longer for biting and poifoning what it feizes. Thefe are only placed in the upper jaw, but all the teeth of the mouth are of the canine kind, as the creature, never chewing its prey, has no ufe for dentes molares, or grinders. The poifon ous teeth are fituated on the outfide of the jaw, in the anterior part of the mouth ; not fixed in the fockets of the jaws, as the others, but fixed to two bones. Thefe, in their natural ftate, are not vifible, even when the creature's mouth is opened, unlefs it be with an intent to wound; .for they lie back under a membranaceous co- vering, and the creature has a power of erecting, and wounding with them at pleafure, as the lion and cat kind can retract, or thruft out their claws. Thefe teeth are crooked, and have a hollow at their bottom, and at their point a very plain and evident flit, looking like the neb of a writing pen. The teeth are hollow all the way from this flit to their bottom, and on prefling the gums in a dead rattle-fiah, the poifonous juice may be fcen to afcend by degrees up the tooth, and at length to be difcharged out of the flit at the point. This makes it very plain in what manner the poifon is conveyed into the flefh, when the creature bites. /
The rattle is affixed to the laft vertebra of the tail, and Is compofed of a fcries of fmall bones ; that next the tail is ufually of a blueifh srey colour, the reft of a pale brown. Thefe bones are hollow, very thin, hard, and dry, and of a brittle texture, and very fonorous. They are all of the fame figure, rcprcfenting, in fome degree, the os facrum in the human fceleton, and all are nearly of the fame fize. The laft of thefe is (eta to have a rigid extremity, in man- ner of a tail, and all the others have the fame, though it is not diftingui Arable in them, as in the joining it runs under two others ; and by means of this ftructure they are all moveable with the fmalleft force, and the found is the more vigorous, as each of thefe tails ftrikes on two of the hollow joints, when put in motion.
The age of the creature is known by the number of joints of this rattle., which are found to be from one to twenty, or more. The ufe of this feems not to the creature, but to other animals, that they may be alarmed at the approach of fo terrible an enemy, and get out of its way in time. Pifo, and fome others, affirm, that this rattle put up a man's fundament, is as fatal a thing as the creature's bite. The power of doing mifchief, which nature has allotted to this animal, feems not only by its bite, but, according to the joint accounts of almoft all authors, it appears to have a power of destroying even by a look. Ray's Syn. Anim. p. 322.
The charming, or fafcination of the rattle-fiah, as this is ufually called, has exerciled the wits of many naturalifts in vain, and many have difbelieved the fact. Sir Hans Sloan mitigates the matter, by fuppofing the creature firft to feize or bite its prey, which it then fuffers to efcape, as far as the poifon will let it, watching its death, that it may devour it without trouble ; and that it is in this poifoned ftate that people have fcen the fquirrels, &fr. dancing about before the ratth-fnah, and dying convulfed ; all which they have attributed to the power of charming in the eye of the fnake, not conceiving that it was the effect of the creature's hav- ing before bitten them. This, though a very plaufiblc ac- count, yet however wants experience to confirm it, and the general teftimony of people, who have feen the facts, makes againft it.
The fame author gives us, however, from Colonel Beverley, the whole proceis of the charm. The colonel acquaints us, that fome company he was with once faw a hare, about
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half grown, filing quietly in an orchard, and (biking « her, fhe only removed a few yards ; when wondering ac the caufe, they faw a rattle-fnake, at about ten feet difta'nee eying the hare as his deftined prey. The poor creature was, by this time 1 , in agonies and convulfions, often getting up on its legs, as' if intending to run away, but always im- mediately falling down again, and growing worfe and worfe, foon loft the ufe of its hinder legs, and panting vehemently, fell on its fide. In about half an hour more the hare feemed to have done with all ftruggles, and to be dead, on which the fnahe uncoiled itfclf, and moved gently towards it, but \ the poor hare flatting again, he ftopt ; but when all was again quiet, he moved up to it, and, raifing his head, look- ed all over his prey ; his colours looking at that inftant more beautiful than before, and his eyes fparkling. The hinder part of the hare had been toward the fnake all this time, and it had perifhed without much looking at its ene- my. The fnake wetted the body all over with his flavor; and then, with great difficulty, taking firft the head into his mouth, fwallowed that, and afterwards the whole body, fucking it gently down, and not getting in the fhoulders without great difficulty.
It is certain, upon the whole, that there is much in this account to favour Sir Hans Sloan's opinion of the hare's having been firft bitten, though that was not feen, fines the convulfions, and lofs of the ufe of the hinder legs, feem a very natural effect of poifon ; but we are affined, by perfons who have been eye-wknefles to the fact, that a bird hopping about in all this agony and terror, has, on the frightning the rattle-fnake away, flown off without any difficulty ; fo that the whole feems yet not underftood. Sloan's Hift. Jamaica. Beverley & Virginia. RAUCA avis, in zoology, the name of a bird defcribed by Nieremberg, as common about the lakes and rivers ofA- merica, and of the king-fifher kind, but nearly as large as a duck, and black on the crown, and white on the breaft and belly. Its neck is naturally very long in proportion to its body, yet it can occafionally contract and Shorten it in a very wonderful manner. It is a native of Mexico, and is efteemed very good for the table. Mr. Ray has placed this among the birds, the accounts of which he is diftruftful of. Ray's Ornitholog. p. 300. RAUCEDO, boarfenefs, in medicine, the name of a difeafe which confifts in the conftriction of the glandulous coat, and other glandular parts, near the top of the wind-pipe, by means of which the due quantity of lymph, deftined to lubricate the wind-pipe, is not fuffered to flow to its place. This diftemper differs in degree, being milder when from external caufes, and greatly more obftinate and troublefome when from internal. Signs of it. The boarfenefs of the voice in fpeaking fuflici- ently manifefts this complaint, but it is ufually alfo attended with a flight cough in the milder kind ; and when of the feverer fort, is not unfrcquently accompanied with catarrhal and fcorbutic effects ; and not uncommonly, in its worft States, with a complication of venereal taints. The perfons moft fubject to boarfeneffes are young and middle-aged men, and fometimes women, who have for fome time been af- flicted with obstructions of the menfes. Caufes of it. The general caufe of an boarfenefs is an inter- ception of the lymph deftined to lubricate the wind-pipe ; and the occafional caufe of this is ufually an obstruction of the glandular parts, toward the top of that organ, in the fimple rata eds ; but in the complicated kind, in which there is a fcorbutic or venereal taint, an erofion of the epiglottis is very often the caufe. Befide thefe, there are many acci- dental and external caufes, which will bring on a boarfe- nefs ; fueh as the falling of any fmall particle of extrane- ous matter, if it be only a grain of duft, into the wind- pipe ; a vehement cough will alfo bring it on, as will a frequent loud fpeaking, and too fat foods, and acrid or bi- lious humors stagnating about thefe parts. It is eafy to conceive, that the more complicated this difeafe is, the more difficult will be the cure ; and accordingly boarfeneffes, which have fcorbutic or venereal taints for their bafis, are with great difficulty removed. Method of cure. Lubricating medicines are firft to be given, to obtund the acrimony of the humors, and relax the ftric- tures of the glandular parts. To this purpofe are properly taken oil of almonds, and the pectoral fyrups, with barley water, mucilaginous broths, and decoctions of the pectoral herbs, or infufions of them drank in the manner of tea. When there is a coryza, or cough attending it, thefe are to be treated in the ufual way, and the boarfenefs will ufu- ally go off with them. When acrid and bilious humors are in the cafe, the abforbents and nitrous medicines are to be given, with gentle diaphoretics ; powders compofed of crabs eyes, nitre, and diaphoretic antimony, are of great ufe in this cafe. The bowels, in all thefe cafes, are to be kept gently relaxed ; and where there is a fcorbutic, or ve- nereal taint for the bafis, thofe difeafes mult be attacked in the common way, and then the boarfenefs will be regularly taken off. A relaxation of the wind-pipe is ufually accufed as being the caufe of a boarfenefs, and that not without a lams
