ACONITUM. 



ACOUSTICS. 



68 



of aconite not to apply too high a temperature. The same pre- 

 caution ie required informing the extract or inspissating the juice. ^ A 

 knowledge of this fact leads to the most convenient and effectual 

 antidote in cases of poisoning by these plants, viz., causing the patient 

 to drink very warm water till vomiting is excited. Liumcus saw 

 aconite disarmed of its virulence, so that it could be used as a pot-herb, 

 by merely boiling it, and adding a little fat or butter. (Linntcus, ' Flora 

 Lapponica,' p. 187, ed. Lond. 1792.) 



The fatty oil is destructive of the sensibility of any part to which it 

 is applied, but whether from inherent powers or from having aconitina 

 dissolved in it is yet unknown. The alkaloid is regarded as the 

 efficient principle when aconite is used medicinally. The forms of 

 administration are various. Powder is objectionable from the variable 

 degree of power. This further varies with the period when the leaves 

 are collected. The best time to gather them is immediately before the 

 flowers wither, as when the seeds advance to maturity the acrimony of 

 the leaves rapidly diminishes. (Christison.) When the seeds are 

 intended to be collected, this should be done just before they are 

 perfectly ripe. The root should be taken up before the flowers 

 expand ; it must be carefully, yet speedily dried, at a very low tempe- 

 rature, otherwise it soon becomes mouldy and its activity is impaired, 

 while a high temperature quite dissipates its valuable properties. The 

 watery extract is a worthless preparation ; and the inspissated juice of 

 the ' London Pharmacopoeia,' improperly termed an extract, is also 

 objectionable. All these anomalies, and the diversity of strength of 

 the different preparations enjoined by the different pharmacopeias of 

 London, Edinburgh, and Dublin, from the existence of which, serious 

 consequences often result, will in future be avoided, by the publication 

 of the ' National Pharmacopoeia,' ordered to be prepared under the new 

 Medical Bill. Besides the officinal preparations, various popular ones 

 exist. Of the scientific ones, Dr. Fleming's tincture is the best. It 

 requires great care in iU use. An excise officer lost his life, from 

 merely tasting it (' Journal of Pharmaceutical Society," vol. xi. p. 237). 

 A spurious aconitine is prepared in France, and imported into this 

 country. It is devoid of the valuable properties of the genuine, the 

 high price of which offers too great a temptation to fraud. The 

 best forms are either an alcoholic extract of the leaves, or an 

 alcoholic tincture of the root made by displacement. The inactivity of 

 the watery extract and inspissated juice has led to statements in some 

 ]ipular treatises that it may be given in the dose of twenty grains, a 

 quantity which would prove fatal when the extract is prejared with 

 alcohol. Of this latter it is rare that two grains can be given with 

 : a quarter of a grain is sufficient to begin with. Possessing 

 narcotico-acrid properties, the action of aconite on the human frame is 

 different according to the quantity used. In small medicinal doses its 

 most obvious action is purely local ; in larger, its action is both local 

 and remote. Thus a small portion chewed produces an immediate 

 action, tingling, followed by numbness of the lips and tongue ; increased 

 secretion of saliva also occurs. Minute doses taken into the stomach 

 cause augmented secretion both of the mucous membrane and of the 

 glands in the vicinity, the secretion of the liver is often markedly 

 increased ; while tingling of the extremities, with heat, is often felt, 

 .mil either jierspiration or increased action of the kidneys. The 

 < m the pupil is variously stated. Geiger affirms that acouitine 

 produces dilatation of the pupil, Dr. Pereira most positively asserts, in 

 hi-i Materia Medica, that the external application of it produces con- 

 traction ; while in his experiments with the extract of the Am- 

 ii it a HI fens (recorded in ' Edinb. Journ. of Natural and Oeograph. 

 Science,' July 1830, p. 235) he distinctly states that while the 

 .mini.il continued alive the pupils were ' much dilated,' contraction 

 taking place only after the animal was apparently dead. Large doses 

 cause redness and inflammation of the parts brought in contact with 

 it ; but the intellectual powers do not seem impaired by it, even when 

 a fatal result occurs. Sir B. Brodie thinks that it occasions death by 

 ying the functions of the brain. ('Phil. Trans.' 1818, p. 186.) 

 Fur this effect he does not consider absorption necessary; while Dr. 

 I'.i.'inv concludes from his experiments, that the intensity of its 

 >i; action on the nervous system is in proportion to the alworbing 

 powers of the part to which it is applied (' Kdinb. Jour.' p. 242). 

 Tli>- -MHCfptiliility of the heart to galvanic agents is greatly impaired 

 by it. 



When first introduced into medical practice it was recommended in 

 many diseases ; but it is now almost entirely restricted to painful 

 affections of the nerves, and to rheumatic complaints, particularly when 

 they are complicated with syphilis. For nervous affections it is more 

 ii->"l externally than internally, but this last mode is to be commended 

 ;it the same time. An ointment is formed with one or two grains of 

 mi tine to one drachm of axunge. A small portion of this is to 

 be applied frequently to the part affected. An eruption sometimes 

 appears, especially if the ointment be strong. The internal use of 

 aconitine is scarcely to be advised, one-fiftieth of a grain having en- 

 dangered the life of an adult. The very high price of this article is an 

 obstacle to it* extensive employment ; but ingenious chemists are 

 endeavouring to simplify the process of extracting it. To obtain it 

 perfectly pure it is almost essential to use sulphuric ether in the pre- 

 ]<ir .ition of it, which necessarily increases the expense. The alcoholic 

 tincture or extract u of great service in chronic rheumatism, and even 

 i of acute rheumatism. 



Should poisoning occur, no time is to be lost, as it has proved fatal 

 in one hour after being eaten instead of horseradish, at Bristol (' Jour, 

 of Pharmaceutical Society,' vol. xiii. p. 294). Animal charcoal has been 

 recommended as an antidote. But even if really useful, it is only 

 serviceable when quite freshly prepared, in which state it is rarely to 

 oe had promptly. The best mode of proceeding is as soon as it has 

 been ascertained that Monkshood has been taken, if the root or leaves 

 bave been eaten to endeavour to empty the stomach as quickly as 

 possible. Warm water alone, or with flour of mustard in it, will 

 generally effect this ; or a stomach pump, if at hand, may be used. 

 Perhaps magnesia diffused through, the water may be useful. But 

 ' abundance of very warm water ' is good alone. Afterwards harts- 

 horn, properly diluted, tincture of cardamoms or brandy may be given. 

 The patient should be kept walking, if possible. Should inflammation 

 ensue, venesection may be needed. 



ACOUSTICS is sometimes divided into the science of hearing (from 

 OKOVU, to hear), and that of sounding or PHONICS (from tpwv^], sound}. 

 It is not necessary to attempt to define what sound is, or to dwell on 

 the fact that some sounds differ only in intensity or loudness, as the 

 reports of a cannon and a musket ; others in musical pitch, as two notes 

 of the same instrument ; others again in character or tone, or, as the 

 French call it, timbre, such as the same note sounded on a flute and a 

 trumpet. These differences being understood, we proceed to inquire 

 by what agency these different sounds are conveyed to the ear ; in 

 what manner the ear is acted upon by sounds of different loudness, 

 tone, and character ; and how far we can explain the remarkable fact 

 that we can hear and distinguish, at the same time, almost any number 

 of different sounds. Unfortunately, our knowledge is limited by the 

 nature of the question, which requires the improvement of one of the 

 most difficult branches of mathematical analysis; and by our very 

 imperfect knowledge of the constitution of matter, and the effect which 

 the putting in motion of some particles of a body has upon the other 

 particles. Strictly speaking, we ought to say, that sound has no exist- 

 ence except in the mind of the hearer ; but, in accordance with common 

 phraseology, we shall speak of a body as sounding when it is hi that 

 state in which it would produce the impression of sound, if the proper 

 medium were placed between it and the ear. 



No body can produce a sound, as we know from observation, unless 

 itri jwirts be put into rapid motion. We have evidence of this in a 

 tuning fork, the string of a musical instrument, the parchment-head 

 of a drum, Ac. Neither will any sound be perceived unless there is a 

 continual supply of solid or fluid matter, possessed of a moderate 

 degree of elasticity, between it and the ear. Thus, a bell, when rung 

 in the exhausted receiver of an air-pump, yields hardly any sound ; 

 and the small portion which it does give may be destroyed or mate- 

 rially diminished by lining the receiver with cotton or wool ; or still 

 better, by exhausting the receiver as much as the air-pump will allow, 

 then tilling it up with pure hydrogen gas and again exhausting. The 

 air is generally the medium through which sound is conveyed ; but 

 only because this is most commonly the one with which the memorana, 

 f/niifinii or membrane of the drum of the ear is iu direct communica- 

 tion. A bell rung under water has been distinctly heard by M. Colladou 

 across the whole breadth of the lake of Geneva, a distance of 9 miles, 

 the sound being observed to pass through the water with a velocity 

 of 4708 feet per second ; those who work in one shaft of a mine can 

 often distinctly hear the sound of the pickaxe in another shaft through 

 the solid rock ; and persons wholly deaf, who therefore are not at all 

 affected through the ear, have received pleasure from music, by placing 

 their hands upon a shutter or other solid body near the instruments. 

 Biot's experiments, too, have shown some very curious results of the vary- 

 ing velocity of sound for different media. He fixed a bell at the end of an 

 iron tube of about 3120 feet in length, and he found that the sound of 

 the bell was double as heard at the other end, the first sound being 

 transmitted through the metal, and the second through the column of 

 air in its interior. He also found that the slightest whisper at one end 

 was distinctly communicated to the other. To this fact he added the 

 observation, that the well-known double report of a musket is owing 

 to the same cause, the sound being unequally carried through the air 

 and the vapour floating in it. In the following remarks we will con- 

 fine'our attention to what takes place in air during the production of 

 sound. 



The Ixxly of air which surrounds us produces no sound if it be all 

 moved together, that is, if the velocity of all its particles be the same : 

 the highest wind makes no noise except when it is forced against some 

 obstacle ; but the sound of a cannon is heard in whatever direction the 

 wind may blow : it may also be remarked, that the strongest band of 

 music does not produce any sensible wind in any direction. It is 

 therefore to some other kind of motion that we must look for the 

 agent of sound, and the manner in which sonorous bodies move 

 immediately points it out. If a tuning-fork or string be struck, a rapid 

 succession of vibrations is the consequence, which, as we shall see, 

 causes the particles of air to vibrate in a similar manner. We find, 

 moreover, that in order to produce a note, there must be not only a 

 succession, but a rajiid succession, of vibrations. Now, experiments 

 show that the ear is not capable of receiving the impression which we 

 call sound, unless the particles of air in contact with it vibrate at least 

 30 times in a second. The vibration produced in the particles of air 

 by a sonorous body may be distinctly proved by the following expcri- 



