POINDING. 



POISON. 



694 



or hearer, and thus imitate the action of those impulses which hav< 

 previously excited such feelings in his own mind. Most short com 

 positions intended to be sung belong to this class. If the tone o 

 thought is enthusiastic and the metre irregular, we call the work an 

 ode ; if it express tender or mournful feelings in a more regular form 

 it is an elegy ; the name of " sonnet " marks the outward form only 

 Perhaps no general word can be found so applicable to the greater 

 part of those compositions, which are neither epic nor dramatic, as 

 the term " lyrical," though it does not seem in any usual sense to 

 include epigram, satire, or didactic poems. 



The different classes of poetry are further treated of under the heads 

 BALLAD, DRAMA, EPIC POETRY, LYRIC POETRY, ODE, ftc. 



POINDING, in -the law of Scotland, is a process for enforcing pay- 

 ment of a debt, against the property of the debtor. It is divided into 

 " personal poinding," and " poinding of the ground." The former is 

 the method by which any ordinary creditor attaches the moveables ol 

 his debtor ; the latter is peculiar to the holders of real rights over 

 estates belonging to others as to superiors entitled to feu duties or 

 the holders of real securities entitled to payment of the interest who 

 can by this process attach the rente or other proceeds of the estate, 

 and pay themselves. Personal poinding is the most usual form it 

 is of very frequent occurrence, and is a rapid and effective process, 

 analogous to the " distress" of the law of England. 



POINT, in Music. [FCGUE.] 



POINT. [SOLID, SURFACE, Lnnt, POINT, DEFINITION OF.] 



POINT OF CONTRARY FLEXURE. By this term is understood 

 a point at which a curve changes its curvature with respect to any 

 given external point, being concave on one side and convex on the 

 other. [See the figure in CURVE for instances.] 



The mathematical test of a point of contrary flexure in a plane 

 curve is as follows : Let y = $x be the equation of the curve, and let 

 y" be the second differential coefficient of y with respect to r. As long 

 as y and y" have the same sign, the curve presents its convexity to the 

 axis of x and when y and y* have different signs, its concavity. 

 When y" changes sign, there is a point of contrary flexure, if y be then 

 finite ; and this, whether it passes through zero or infinity at the 

 change. (Library of Useful Knowledge, ' Diff Calc.,' pp. 369, 370.) 



It is frequently stated in elementary works, that there is a point of 

 contrary flexure when y" = 0, and the converse. Both propositions are 

 inaccurate : there is not necessarily such a point when y" = 0, and there 

 may be such a point when y" is not nothing, but infinite. 



1 2 



For example, let y = x 3 -, which gives y" = 2 . A* long as x is 



less than 1, y" is negative, and so is y, whence the curve is convex to 

 the axis of x. When x=l, both y and y" vanish, and when x is greater 

 than 1 , y and y " are both positive, so that the curve is still convex. 

 But there is a change of sign in y" when x passes through 1 ; and there- 

 fore there is a point of contrary flexure when x = 1. It is to be re- 

 membered that though at a point of contrary flexure the curve changes 

 curvature with respect to any line not passing through the point, it 

 preserves its curvature with respect to every line which does pom 

 through the point, being on both sides convex, or on both sides con- 

 cave, to that line. In the present instance, the curve is always convex 

 to the axis of x ; consequently, where it has a point of contrary 

 flexure, it cuts that axis. 



At every point of contrary flexure, the TANGENT passes through the 

 curve, and has a contact of an order different from that which it usually 

 has. The radius of curvature at a point of contrary flexure is always 

 either nothing or infinite. 



Some English writers have copied the Continental ones in calling it 

 a point of injitxim. 



POISON. Separate articles having been devoted to nearly all the 

 substances which are destructive to life when taken by accident or 

 design, or when administered with a criminal intention, it will be 

 necessary here only to consider the subject of poisons generally, 

 referring to the articles ARSENIC, ANTIMONY, COPPER, MERCURY, 

 PAPAVKR, &c., for the details relating to each of them in particular. 

 The whole subject may be conveniently and usefully treated by point- 

 ing out how in any case of legal investigation the proofs of poisoning 

 may be established. 



ting those things which are common to all cases of suicide or 

 homicide, such as the previous circumstances of the person supposed 

 to be poisoned, the conduct of the accused, and those, however im- 

 portant they may be, that are matters of common evidence, such as a 

 number of persons who have partaken of the same meal being simul- 

 taneously and similarly affected, we propose to consider here only how 

 in any individual case the influence of poison may be proved. The 

 chief circumstances in the evidence will be, the symptoms presented 

 during life : the examination of the body after death ; the chemical 

 analysis of the substances in which the poison may be mixed ; and the 

 experiments by which it is attempted to produce similar circumstances 

 in animals by similar means. 



The circumstances that usually first excite the suspicion of poison 

 having been taken are, that the person affected is suddenly attacked 

 by symptoms of severe illness, which come on soon after eating or 

 drinking, without any premonitory indications, which regularly in- 

 crease in severity without undergoing any important change in tlu-ir 



ARTS A.VD SCI. JIV. VOL. VL 



character, and which rapidly prove fatal. All these however are far 

 from affording sufficient evidence of poisoning. Suddenness of attack 

 is common to many disorders, as cholera (whether ordinary or Asiatic), 

 plague, perforating liberation of the digestive canal, apoplexy, and 

 epilepsy ; and even in some cases of fever the premonitory symptoms 

 are too slight to attract the attention of the patient. Any of these 

 too may come on soon after taking food, and while the patient is 

 apparently in the enjoyment of health ; this is especially the case with 

 cholera, perforation of the stomach, and apoplexy ; and even in some 

 diseases of the heart the patient may seem well up to the instant of 

 the fatal, and often instantly fatal, seizure. The permanency and 

 regular increase of the symptoms is not a more distinctive sign of 

 poisoning. It is equally observed in many cases of the diseases already 

 mentioned, as well as in most acute and uncontrolled inflammations, 

 strangulation or other obstruction of the intestines, &c. Many of these 

 diseases also may prove very rapidly fatal ; apoplexy and certain dis- 

 eases of the heart sometimes destroy life in a few seconds, and often in 

 a few hours ; in almost all cases of perforation of the digestive canal, 

 and in some of cholera, death takes place in less than twelve hours. 



In no case therefore can these, which are commonly stated as general 

 symptoms of poisoning, excite more than suspicion ; they may all have 

 been produced by some spontaneously occurring disease. But on the 

 other hand, the absence of any or all of them is not sufficient to dis- 

 prove the suspicion of poisoning. Small and often repeated doses of 

 poison may be given so as to produce all their symptoms and death 

 very gradually ; and the patient may in such a case exhibit numerous 

 alternations of increase and moderation of the symptoms. Many cir- 

 cumstances will retard the action of even large doses of poison ; if a 

 person falls asleep soon after taking one, or if he has taken it with a 

 large quantity of food, or much diluted, or partially neutralised, its 

 symptoms may not be developed for some hours, and may seem quite 

 unconnected with the last occasion of taking food. Or again, the 

 poison may be administered in some other way than with food or 

 medicine, as in the form of a vapour, by applications to the ulcerated 

 skin, &c. 



Dr. Christison divides poisons into three classes, irritants, narcotics, 

 and narcotico-acrids. Each of these produce certain symptoms in 

 addition to those already mentioned as belonging to poisons of all 

 kinds, and certain morbid effects upon the organs of the body when it 

 proves fatal, by which their action may in some cases be recognised. 



The chief symptoms caused by the internal administration of irri- 

 tant poisons are those of severe irritation of some or all parts of the 

 alimentary canal. They commonly excite burning heat, redness and 

 swelling and sometimes ulceration of the lining of the mouth, throat, 

 and tongue; difficulty of swallowing, burning pain of the stomach 

 with nausea and retching or vomiting, tenderness on pressure and 

 tension of the upper part of the abdomen. The matters vomited con- 

 sist, first, of the food or other contents of the stomach, and afterwards 

 of tough mucus with more or less of blood and bile ; the sickness is 

 almost incessant, and is usually accompanied by severe suffering. The 

 pain commonly extends from the stomach along a part or the whole of 

 the digestive canal, with tenderness on pressure, and usually a con- 

 stant and painful diarrhoea of mucus with more or less blood. The 

 pulse is quick and feeble ; there is great prostration of strength, ex- 

 cessive burning thirst, cold and damp skin, extreme anxiety of counte- 

 nance and manner, and often considerable difficulty of breathing. 



Many or all of these symptoms occur in all cases of poisoning by 

 irritants, and many of them also in certain diseases, between which 

 and poisoning it may be difficult to discriminate. Of these diseases 

 the most important and deceptive are the acute affections of the digestive 

 organs. 



The most general effect of irritant poisoning is acute inflammation of 

 the stomach, and it is therefore a question of the first importance 

 whether that condition is ever produced by any other cause than the 

 administration of poison. M. Louis and Dr. Abercrombie, whose 

 authority is of the greatest weight in subjects of this kind, have stated 

 that they never saw a case (of idiopatbic and primary acute gastritis ; 

 and it is certain that no well-established case of the kind has yet 

 seen recorded : the administration of an irritant poison may therefore 

 je regarded as highly probable in any case in which a competent 

 observer finds the signs of an acute inflammation of the stomach during 

 ife and its effects after death. 



In such cases the principal evidence would depend on the appear- 

 ances found in the dead body ; in others the symptoms during life are 

 equally important. Perhaps of all the diseases which give rise to the 

 suspicion of irritant poisoning, the most frequent is cholera. There 

 are however some circumstances by which they may be distinguished 

 during life. In most cases of this kind of poisoning a burning sensa- 

 tion in the throat is perceived directly after the poison is taken, being 

 the effect of its contact during or soon after the act of swallowing ; the 

 same symptom, when it occurs in cholera, appears to be produced by 

 the contact of the substances vomited, and is therefore preceded by 

 some of the other symptoms. In cholera the vomiting is never bloody, 

 and is usually much more profuse than in cases of poisoning; and the 

 cholera that occurs in this country is very rarely fatal in less than three 

 days ; while in most cases of poisoning, in which the symptoms are 

 uaden and severe, death ensue in a few hours, or at least before the 

 end of the third day. Asiatic cholera indeed is commonly more rapidly 



