Ml 



ASTRIXC 



ASTROI.A 



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of the intestine, or U owing to the 

 ..( any acrid substance, the former may b* overcome by anti- 

 i, and the latter be removed by purgatives. When 

 from the inlorrtim* U ouoneoUd with increased 

 ird thoee parte, owing to the application of col.l u. 

 the Mention of the akin, which has the 



thec 



sisals* sympathy with the internal surface, and which oontequently 

 &eaeHrftobuWeaction,apretcrntural. 1 uanUty of secreteiltlui.l U 

 lauhiiml The moat tffurtii'l. a* well as only safe meant of diminish- 

 Ing this, in the early stages of Ha occurrence, to the employment of 

 aiMOKtice, or tuch medicine* as reetore the action of the skin; after 

 which, should the discharge continue, mild astringents may be used, 

 of which logwood or tormentil to the best. A preliminary treatment 1s 

 likewise required in dysentery : in the common cholera a purgative 

 ahould generally be given before any astringent is administered. 



In the bilious cholera of autumn, after the employment of suitable 

 purgative*, nothing seemi to act more effectually as an astringent than 

 the infusion of cusparia, or angustura bark, with dilute nitric acid ; to 

 which, in tome ottet, a small portion of laudanum may be added at 

 first, but afterward* omitted. Nor in the slighter cases of epidemic 

 cholera, hat more marked benefit followed the use of any 



hat resulted from the employment of this combination, which speedily 

 checkt the liquid discharges, and restores the circulation and animal 



Diarrhoea, or Inmimnen of bowels, proceeding from acid secretions, is 

 best removed by the astringents which combine chemically with these 

 such as lime, or iu carbonate, which ore rendered more suitable by 

 uniting them with aromatics, an excellent form of which is supplied by 

 the ssisniru ereta, or chalk mixture of the pharmacopoeia. 



The next meet important class of diseases in which astringent* may 

 be employed are termed hemorrhages, or a discharge of blood, either 

 from the exhalant extremities of the arteries, when they are gorged or 

 when they are too much relaxed, or from the wounded or ruptured 

 coats of any blood-vessel. The above distinction refers to the differ- 

 ence! between active and passive hemorrhage, or that which takes place 

 when the system is too full of blood and the vessels propel it with 

 great force ; the other, which takes place when the power of the vessel 

 is greatly below the natural standard. In the former, astringents 

 cannot safely be employed at the commencement of the flow of blood, 

 but time ahould be allowed for the vessels to unload themselves ; or a 

 vein should be opened, cooling saline medicines administered, cold air 

 admitted freely to the surface of the body, and, under competent 

 medical attendance, opium or laudanum may be given ; after which, 

 astringents will either not be required, or if so, may be safely used. 



In passive htemorrhage they may be employed from the commence- 

 ment ; and perhaps, in most cases, a saturated solution of alum in the 

 infusion of roses is to be preferred, though the tincture of the muriate 

 of iron is very eligible when the kidney is the source of the bloody 

 discharge, as acetate of lead is when the lungs are the organs whence 

 the blood flows. So long as lead is kept in the state of an acetate, its 

 administration is perfectly safe : it should therefore always be accom- 

 panied with dilute acetic acid. 



Bleeding from the nostrils or gums may be checked by the direct 

 application of styptics; such as preparations ofj zinc or copper. 

 Nitrate of silver will frequently stop the flow of blood from a leech 

 bite ; collodion more effectually still. Cold should, in most cases, be 

 employed along with the other means ; even alone it U often sue 

 ceesful, especially in the form of water poured from a height in 

 uterine tuemorrhage. Ruspini's styptic, which is said to be a solution 

 of gallic acid in alcohol, is sometimes useful, where other means have 

 failed. Matioo is very useful. 



The application of astringents to more limited examples of loss of 

 tone or increased flow of secreted fluids, need not be extensively 

 noticed here. After acute inflammation of the eye, proper antiphlo- 

 gistic means having been used, astringent applications are very service- 

 able, especially those of zinc and nitrate of silver, either in solution or 

 made into an ointment. Scrofulous inflammation of the eye is often 

 benefited by them, if internal means be also used. Salivation, or 

 excessive flow of saliva, occurring either spontaneously or from the 

 use of mercury or other means, is often effectually checked by nitrate 

 of silver, or decoction of the rhus glabrum, or by iodine, or infusion 

 of cloves. Nitrate of silver, by lessening the inflammation which 

 gives rise to them, also frequently removes morbid discharges from 

 other mucous surfaces besides those we have specially noticed ; an 

 effect which also often follows the use of diluted chloride of soda. 

 The coUiquative sweats of hectic fever are best checked by giving 

 internally dilute sulphuric acid, and sponging the skin with vinegar 

 and water, or by oxide of zinc. 



Astringent substances are decomposed by, or decompose, many 

 other*, which therefore should not be given at the same time with 

 them ; such, for example, as ipecacuanha with most of the vegetable 

 astringents which contain tannin, by which an insoluble Unnate of 

 etnetina is formed : when kino is united with calumba, a purgative 

 action follows. All astringent vegetable* containing tannin, except 

 oak-bark, decompose tartrito of antimony, and are therefore the best 

 antidotes to it, especially tea. 



The ancient Egyptians would appear to have been acquainted with 

 the power of astringent* in preserving vegetable as well a* animal 



substance*, and they seem to have dipped the coarse cloths in which 

 he mummies were enveloped in some aililiigsjil liquid, which tanned 

 he akin, and rendered it less subject to change, as well as excluded 

 the air from the interior of the body. The article employed by them 

 with this view U supposed to have been tome sort of kino. The same 

 suUUnce is said to be used by the Chinese to dye cotton for their 

 ntnknnnt. but perhaps a peculiar cotton. 



This property of astringent* may be usefully applied for the pre- 

 servation of all kinds of cordage, fishing-lines, and nets, which but 

 much longer if steeped in an infusion of oak-bark. Though inferior in 

 snseiving power to the plan of Mr. Kyan, it may be applicable in some 

 sales where his is inadmissible. [ ANTISEITICH.] 



For further information on astringents, see Dr. A. T. TK 

 Elements of Hateria Medioa and Therapeutics,' vol. ii., in !,:, I, 

 much recent valuable matter is brought together. 



(For the employment of astringent* in the arts, see DYKIXO AND 

 TAXSTSG; and also ' Library of Entertaining Knowledge' Vegetable 

 Substances; Mtterialt of Manufactures, p. 178, 1st edition). 



ASTROLABE, from two Greek words, signifying to tain tht Han. 

 \l has an earlier and a later meaning. As used by Ptolemy, it may 

 stand for any circular instrument used for observations of the stars ; 

 but in the 16th and 17th centuries it signified a projection of the 

 sphere upon a plane, being used in the same sense as the word 

 J'laninjihart. To this small projection, which had a graduated rim. 

 sights were added, for the purpose of taking altitudes ; and in this 

 state it was the constant companion and badge of office of the astrologer. 

 In later times, before the invention of Hadley's quadrant, a graduated 

 circular rim, with eights attached, called an astrolabe, was used for 

 taking altitudes at sea, as further described in Bion, ' Trait<5 des Inntru- 

 meiiH de Mathematique,' Hague, 1723. In the older sense of the w..r.l, 

 every one of our modern astronomical instruments is a part of the 

 astrolabe, the principle of which we proceed to describe. 



If a solid circle be fixed in any one position, and a tube be fixed ngxin 

 its centre, round which it may be allowed to move, as in the M'ljoiniiiK 

 diagram ; and if the line D be drawn upon the circle, pointing towards 



any object Q in the heavens which lies in the plane of the circle, ii i~ 

 obvious that, by turning the tube A B towards any other object P in tin- 

 plane of the circle, the angle BOD will be the angle subtended by the 

 two objects p and Q at the eye, or their angular distance upon a com- 

 mon globe. This angle may be measured, if the circumference of the 

 circle be graduated. Thus, suppose the plane of the circle to pasa 

 through the poles N and 8, and C D to point towards the equator ; 

 then when the tube points towards the star, N o B its north polar dis- 

 tance, or BOD its declination, may be measured ; or if the circle be 

 fixed in the plane of the equator, and c D be made to point towards 

 the vernal equinox at the same moment at which the tube points 

 towards the star, then the angle DOB will be the right ascension of 

 the star. 



A collection of circles, such as the Armillari/ S/>lic re, might therefore, 

 by furnishing each circle with tubes, be made a complete asti 

 The practical difficulty consists in keeping so many circles exactly in 

 their proper relative positions. The distinction between the astrolabe 

 of the ancients and the circular instruments of the moderns, is as 

 follows : First, the ancients endeavoured to form an astrolabe of two 

 circles, so as to measure both latitude and longitude, or both right 

 ascension and declination, by the same instrument ; v, -hile the moderns, 

 in most cases, measure only one of the two. Secondly, the ^ 

 instruments were made to revolve, to find the star, or were furnished 

 with at least one revolving circle, moving round the jwle of the eqn.it. T 

 or ecliptic, according as declination or latitude was to be me,. 

 The moderns for the most part fix their instruments in the. mo.riili.iii 

 and wait for the star. But the tqunlnrial, the altitude and azimuth 

 fircfe, and the theodolite, are strictly astrolabes, according to the ancient 

 meaning of the term. 



lli|.|archun is the first we know of who can be reasonably supposed 

 to have made use of an astrolabe. But, at the same time, there are 

 reasons for supposing that Eratosthenes, a century bef. u. EUpptrohos, 

 made use of a circle fixed in the meridian, for measuring the obliquity 

 of the ecliptic. He is also said to have erected arniillary circles at 

 Alexandria. I'tolemy does not mention Hipparchus expressly ; but he 

 was in all respects his follower, and therefore, proKibly, in describing 

 his own instrument, he is only repeating that of his great predecessor. 

 \ ml Nil li..l.is Cabasillas (an ecclesiastic of the 14th century, cited by 

 Delainbre) attributes to Hipparchus an instrument consulting of an 



