ALT 



A L T 



can only be changed by fir(t changing the a£l:on of the fo- 

 lids, and this opinion is at prefcnt gaining ground. 



1« llic third clafs may be placed inch us aft on the nervous 

 fyftem, often called Axodyses, Emollients, &c. 



If we employ the tenu aheralh-c in a move extended fcnfe, 

 to denote any means bv which an alteration for the better can 

 be produced, \vc llioukl be obliged to refer all diet and medi- 

 cines to this head ; and even with the limitation, of " without 

 a fenliljle operation," we find it no eafy taflc to decide in all 

 cafes what remedies Hioiild be included under alteratives. 



We think a warm or cold climate may act as an alterant ; 

 fo may ifTues or fctons ; others go fo far as to fay that eva- 

 ciiants are the bell alteratives ; others, on the contrary, af- 

 cribe even the falutary eli'efts of evacuants to their alterative 

 nature. This has been alledged of mercury in the cure of 

 the venereal difeafe ; and of it and ipecacuanha in the cure 

 of dyfenteries ; but it mull be obferved that thefe articles 

 fucceed bcft when adminiilered in alierar.t dnjcs. 



The arrangement of the Materia Meuica, as well as 

 the modus operandi of remedies, will furnilh much diverlity 

 of opinion for feveral centuries : it is, fortunately, a ground 

 of difpute that never has, nor ever will materially injure the 

 prad'icj of either medicine or furgery. 



ALTERATA, in Mufc, a term ufed by the French as 

 well as the Italians, for temperament, in fpeaking of inter- 

 vals, and likewife of extreme confonance and dilTonaixe : 

 as an extreme fharp 6th, a redundant jth, an extreme flat 

 7th, &c. 



ALTERATE. See Sesquialterate. 



ALTERATION, Alteratio, in Ph^jlcs, the aft of 

 changing the circumllances and manner of a thing ; its ge- 

 neral nature and appearance remaining the fame. — Or, it is 

 an accidental, and partial change in a body : without pro- 

 ceeding fo far as to make the fubjtft quite unknown, or to 

 take a new denomination thereupon. Or, it may be defined, 

 the acquifition or lofs of fuch qualities as are not effential to 

 the form of the body. Thus a piece of iron, which before 

 ■was cold, is faid to be ahercti, when it is made hot ; fince it 

 may ftill be perceived to be iron, is called by that name, and 

 has all the properties thereof. By this, alteration is dillin- 

 guifned from gen:ration and corruption ; thofe terms cxprefs- 

 ing an acquiiition or lofs of the eifential qualities of a thing. 



The modern philofophers, after the ancient chemiils and 

 corpufcularians, hold all alteration to be effefted by means 

 of local motion. According to them, it always confiits 

 either of the emiffion, accelTion, union, feparation, or tranf- 

 pofition of the component particles. 



Ariftotle makes a peculiar kind of motion, which he calls 

 the motion of alteration. 



Alteration is ufed, in Medicine, to denote a change in 

 the ftate and qualities of an animal body, in refpeft of tem- 

 perature or conllitution, health or ficknefs. 



In this fenfe, alteration includes both evacuation sndaccretion. 



Alteration is more ftriftly taken for a change in the 

 quality of the body, contradiftinguifhed from evacuation and 

 app'iftion. 



In which fenfe, alteration is the effeft of medicines called 

 alterants. 



Alteration is chiefly applied in refpeft of the fluids or hu- 

 mours of the body. When applied to the folids, it is chiefly 

 to afFcft the humours, or the motions of them. 



Alteration is fometimes alfo applied in refpeft of the 

 vital motions of the body. 



Thus fpecifics are applied to alter and reftify convulfivc 

 and other diforderly motions. The alteration of the hu- 

 mours is either cxtrinfie, or intrinfic. The former is a change 

 produced in the fenfible anpearauces, as colcur, thickncit, 



and the like: and the latter is a change in the primitive 

 crails, or conllitution of a fluid. . 



Alteration in a fenfe ilill more ftrift, denotes that 

 convcrfion which the food undergoes, to render it nouriih- 

 ir.ent. In this fcnfc alteration both includes the digeltion 

 performed in the ftomach, and the aflimilation in the habit 

 of the bodv. 



It is difputcd among phyfiologiils what the alteration is 

 which the food undergoes Some reduce it to a mere com- 

 minution or trituration. — Others aflert a total tranfubllanti- 

 ation. See Digestion. 



Alteration of quantities, among Algehraijls, denotes 

 what we otherwife call variation, or permutation. 



AI^TERATIVE, in Medicine, the fame with alterant. 



ALTERCATION, a debate or contcfl: between two 

 friends, or acquaintance. The word comes from altercari ; 

 which anciently fignified to converfe, or hold difcourfe to- 

 gether. Thus, we fay, they never come to an open quar- 

 rel ; but there is continually fome little altercation or other, 



ALTER DO CHAO, in Geography, a fmall town of 

 Portugal, in the province of Alentejo, 12 milts well of Pon- 

 talegre, and 84 eall-north-eaft. of Lilbon. North lat. 39° S'. 

 Well long. 6° 38'. 



ALTERE, a town of Flanders four leagues wefl; of 

 Ghent. 



ALTERIO, a town of Naples, in the province of Cala- 

 bria Citra, 17 miles call-north-eail of Cofenza. 



ALTERN, a town and calile of Germany, in the circle 

 of Upper Saxony, in the county of Mansteld. 



Altern, bafe, a term in Trigonometry, contradiftin- 

 guifhed from true bafe, thus — In an oblique triangle, the true 

 bafe is either the fum of the fides ; in which cafe, the dif- 

 ference of the fides is called the altern bafe ; or the true bafe 

 is the difference of the fides ; in which cafe, the fum of the 

 fides is called the altern bafe. 



ALTERNANTHERA, in Botany, a genus of the tri- 

 andria monogynia clafs and order ; the charafters of which j 

 are, that the cahx has five leaves ; no corolla ; fix filaments, j 

 alternately barren ; the ftigma bifid ; and theyJe^/j- folitary. 

 There is one fpecies, lix. A. repens. Forflc. Fl. ^g. Arab, j 

 p. 28. 



ALTERNATE, or Alternative, is underftood ofl 

 feveral things which fucceed, or are difpofcd after each other 1 

 by turns. 



We fay, an alternate, or alternative ofiice, or truft, which is 

 that difcharged by turns ; fo, two general officers, who com- 

 mand each his day, are faid to have the command alternately. 



In Botany, the term alternate is applied to branches, leaves 

 and flowers, v.'hen, inftead of being oppofite, they fpring out 

 regularly one above another : fuch are the leaves of borrage, 

 or chequered daffodil. See Leaf. 



Alternate, in yfritlimetie. See Alligation. 



Alternate angles, in Geometry, are the internal angles 

 made by a line cutting two parallels, and lying on the oppo- 

 fite fide of the cutting line ; the' one below the firll parallel, 

 and the other above tlie fecoud. 



Thus .V and u, and % and y (Plate I. fig. i. Geometry,) 

 are alternate angles, and thefe angles are equal to another. 



There are alfo two external angles, alternately oppofite to 

 the internal ones. See Parallel. 



A-LTE.Kfi ATE ratio or proportion, is that which the ante- 

 cedents and confequents bear refpeftively to each other in 

 any proportion, which has the quantities of the fame kind. 



Tims, if A : B : : C : D ; then, alternately, A : C : : B : D. 



Alternate, in Heraldry, is ufed in refpeft of the fitu- 

 ations of the quarters. 



Tluis in quarterly eeartele, the firfl and fourth quarters 



are 



