1021 



EXTORTION. 



EXTRAVASATION. 



1033 



EXTORTION. " Extortion," says Coke (Co. Litt., 368, b.), " is a 

 great misprision, by wresting or unlawfully taking by any officer, by 

 colour of his office, any money or valuable thing of or from any man, 

 either that is not due, or more than is due, or before it is due." It is 

 an offence at common law, punishable by fine and imprisonment at the 

 discretion of the court. Also, money which has been obtained by 

 extortion may be recovered in an action at law. There are various 

 stitutes providing penalties for extortion by sheriffs, under-sheriffs, 

 bailiffs, gaolers, clerks of assize, &c. 



EXTRACTION OF ROOTS. [INVOLUTION and EVOLUTION.] 



EXTRACTIVE MASTER. At a period when chemical analysis 

 was less perfect than at present, the term extractive matter was 

 applied to a heterogeneous mixture of matters obtained by treating 

 vegetable substances with water, and then evaporating the solutions 

 to dryness. Improvements in analysis have enabled the chemist to 

 resolve such extractive matter into its constituents, and the term has 

 now become nearly obsolete. 



EXTRACTS are medicinal preparations of vegetable principles, 

 obtained in various ways. Sometimes they are merely the juices 

 expressed from the fresh plants, brought by careful evaporation to the 

 consistence of honey, and then more properly denominated inspissated 

 juices ; at other times they consist of certain principles of the fresh or 

 dried plant extracted by some menstruum in which they are soluble, 

 such as water, proof spirit, vinegar, or ether, and afterwards evaporated, 

 as in the former case. According to the nature of the menstruum 

 employed the extract is called Katery, alcoholic, acetous, or ethereal. The 

 objects proposed in such proceedings are, to ensure the preservation 

 of the active principles of the plant by removing the fluid in which 

 they are dissolved, or the materials with which they are associated, 

 that have a greater tendency to fermentation or putrefaction ; to 

 bring the valuable portion into the smallest possible compass ; and to 

 facilitate the administration of them by thus rendering them capable 

 of being made into pills, &c. 



The preparation of extracts requires the greatest care. The plants 

 must be in every respect of the best quality, as regards the place of 

 their growth, season when collected, &c., and the evaporation must 

 be conducted rapidly, yet at a low temperature. Orfila found that 

 the excellence of preparations of this kind was always in the reverse 

 ratio of the temperature employed to form them. Mr. Barry effected 

 a great improvement in the mode of preparing extracts by evapo- 

 rating in vacua. During the preparation, and especially towards the 

 end of the operation, frequent stirring the contents of the evaporating- 

 pan is necessary to prevent burning or decomposition of any portion 

 of the mass. Extracts may also be formed from dried plants, barks, 

 roots, &c., by reducing them to fine powder and macerating it for 24 

 or 48 hours in sixteen times its weight of water. In general cold 

 water is now employed, but in some cases it is proper to employ warm. 

 The extract of cinchona, prepared with cold water, is less powerful 

 thau that prepared with warm. 



Extracts are simple or compound, according as they are prepared 

 from one plant or from several different kinds. 



This mode of preparing vegetable principles is generally unsuitable 

 where a volatile oil is the active agent, unless great care and a very 

 low temperature be used. 



A well-prepared extract should possess in a great degree the odour, 

 and especially the taste, of the plant from which it is obtained ; it 

 should not have either an empyreumatic smell or taste, and it should 

 have a proper and uniform consistence. It is necessary to preserve 

 extracts in a dry situation : to assist in keeping watery extracts, it is 

 customary to sprinkle a little alcohol over the surface before covering 

 them up ; but watery extracts, if made with cold water and due care, 

 rarely require this precaution. It is proper to examine the condition 

 of all extracts very frequently, both during very warm and very wet 

 weather : any portion which seems spoiled should be immediately 

 thrown out. 



Formerly, from the careless or unskilful mode of their preparation, 

 extracts were the most uncertain and useless form of vegetable remedies ; 

 but since competent practical and scientific chemists have given their 

 attention to the subject, they are now, in many instances, the most 

 valuable contributions which chemistry has made to practical medicine. 



The term is also absurdly applied to a solution of diacetate of lead/ 

 called, after its discoverer, Goulard's Extractor Extract of Saturn. This 

 is only used externally. 



EXTRAORDINARY RAY. When a pencil of light falls upon a 

 doubly refracting crystal, such as one of Iceland spar, it is separated 

 into two rays, one of which is refracted according to the ordinary law, 

 and is termed the ordinary ray ; the other, according to a new or 

 extraordinary law, and is called the extraordinary ray. [POLARISATION 

 OF LIGHT.] 



EXTRAORDINARY REFRACTION. [MIRAGE.] 



EXTRAVASATION (extra, without, vat, a vessel), in medicine, 

 (signifies the escape of any of the fluids from its natural reservoir 

 or canal into some neighbouring cavity or texture. The term is nearly 

 synonymous with effusion, but less comprehensive, as it does not include 

 the case of fluids poured out by secretion, such as dropsies, or any of 

 the products of inflammation. It is most commonly employed in 

 designating effusions of blood or of urine ; and we shall therefore con- 

 fine what we have to say on the subject to a brief notice of the principal 



varieties of these accidents, referring the reader for toore complete 

 information to other parts of the work. 



Extravasations of blood are always serious, and oftpn fatal, -when the 

 larger vessels and more important organs are concerned in them. Th u3 

 if blood escape in consequence of the rupture of an aneurism O f the 

 aorta into the bag which encloses the heart, the circulation is immedi- 

 ately arrested, and sudden death ensues. Such an accident ig said to 

 be "an extravasation of blood into or within the pericardium." 

 [ANEURISM.] 



Blood is sometimes driven with great force from a ruptured or 

 wounded artery into the loose spongy substance consisting of con- 

 nected cells which surrounds and separates the various organs, and is 

 found in great abundance in every part of the body. This is called 

 " extravasation of blood into the cellular tissue " of the part. In such 

 cases, if the vessel be a large one, the extravasation may be so consider- 

 able as to occasion enormous swelling and distension of the contiguous 

 parts ; and it may be fatal from the amount of the hemorrhage, or 

 from pressure upon some vital organ, or from mortification. [HAEMO- 

 RRHAGE.] This is a frequent source of danger in gunshot wounds. 

 Fractures also are generally followed by considerable effusions of the 

 same kind, which however are soon absorbed, and are not often attended 

 with serious consequences, except in fractures of the skull ; in that 

 case they compress the brain, and produce the symptoms of apoplexy. 

 [HEAD, INJURIES or THE.] The thrombus, or swelling beneath the skin, 

 so frequently observed after bleeding from the arm, is also formed by 

 extravasation of blood into the cellular tissue. It arises from the 

 puncture in the skin not corresponding with the opening in the vein, 

 or not being sufficiently large. It soon disperses, and is of little im- 

 portance. [BLEEDING.] Contusions are likewise followed by extra- 

 vasation of blood into the cellular tissue under the skin, and in the 

 skin itself, from the rupture of small vessels ; and this is the reason of 

 the dark colour assumed by the bruised parts, which often extends to 

 a considerable distance from them, as in the familiar instance of a black 

 eye. This superficial extravasation is generally called ccchymvsts, a 

 word of the same import. 



Spontaneous extravasations of blood, allied to those last mentioned, 

 frequently take place in the progress of various diseases, of which 

 they may be causes or symptoms. The spots which appear under the 

 skin and beneath the membranes which line the internal cavities and 

 tubes, in plague, typhus fever, sea scurvy, and other complaints, are of 

 the symptomatic kind ; and these, as well as the discolorations after 

 contusions, are included in the general term ccchymosis ; they are also 

 known by various other names, as vibices (wheals), petechice, and purp lira. 

 They are frequently attended with bleeding from the mucous mem- 

 branes of the intestines and bladder, and of the nose ; and they often 

 occur, in the lower extremities especially, when the liver is enlarged, 

 or otherwise diseased. They are supposed in general to indicate a want 

 of tone in the system, and are attributed by some to a dissolved and 

 semiputrescent condition of the blood ; but they arise in some instances 

 from a plethoric habit, and require bleeding for their cure. 



One of the most common causes of apoplexy is an extravasation of 

 blood in the substance of the brain, or between its membranes, from 

 the simultaneous rupture of many minute arteries. It happens for the 

 most part suddenly, when the vessels of the head are preternaturally 

 distended, but yet not without some premonitory signs ; and as the 

 affection occurs most frequently at an advanced period of life, when the 

 arterial system in general is disposed to disease, it is probable that the 

 rupture is often preceded by some morbid change which renders the 

 capillary vessels more than usually fragile. [APOPLEXY.] The ternj 

 apoplexy has been extended by modern pathologists to similar extra- 

 vasations occurring in the texture of other organs besides the brain ; it 

 may take place in the liver when the venous system of the abdomen is 

 loaded with blood, and from other causes ; and it frequently happens 

 in the lungs when their circulation is either obstructed or too forcibly 

 urged in various diseases of the heart. [HEART, DISEASES OP THE.] 

 It likewise happens very commonly in the early stage of consumption, 

 when the body is yet full of blood, and the substance of the lungs is 

 rendered brittle and inelastic by the deposit of tuberculous matter. 

 [PHTHISIS.] When it occurs in the lungs, the injury is attended with 

 hcemoptyins, or spitting of blood. In this, as in many extravasations of 

 the same kind, it is probable that the blood is effused rather in conse- 

 quence of a rent, or breach of continuity in the structure concerned, 

 than from what is implied in the common notion of the breaking of a 

 blood-vessel. But in the early stage of consumption, the blood almost 

 always escapes by exhalation from the extremities of the relaxed and 

 distended vessels. See Louis ' On Phthisis Pulmonalis,' 



The presence of extravasated blood does not in itself produce much 

 irritation, and the coagulum is soon absorbed when the quantity is not 

 very great, and the vital powers are not depressed by concomitant 

 causes. Where pressure is applicable, the absorption is much quickened 

 by a bandage put on after the immediate effects of the injury have 

 subsided, as in sprains and bruises of the limbs j friction and embro- 

 cations have the same effect. See ' An Essay on the Metamorphosis of 

 the Coloured Blood Corpuscles in Extravasated Blood/ by John Burdon 

 Sanderson, M.D., Edinb., 1851. 



Extravasations of urine may take place in consequence of rupture of 

 the bladder or urinary passages from ulceration, mechanical injuries, 

 or any cause that produces distension to a great degree. If the fluid 



