%% RWD Nickalls 2006
%% made into a .tex file
%%  (from a HTML file on Wright's anaesthesiology web site)
%% needs checking
%% I have stripped off all the html stuff

\documentclass[a4paper]{article}
\usepackage{url}
\begin{document}

\title{Insensibility during surgical operations produced by 
      inhalation.}
\author{Bigelow HJ}
\date{Boston Med Surg J (1846); \underline{35}, 309--317}
\maketitle

\begin{center}
\begin{minipage}{8cm}\textsl{
This \textsc{pdf} version made by RWD Nickalls\footnote{Department of Anaesthesia, Nottingham University Hospitals, City Hospital Campus, Nottingham, UK. 
{\newline} email:\,\textsf{dick@nickalls.org}
[\textsf{}www.nickalls.org/dick/]} (2006) from the \textsc{html} version uploaded by AJ Wright (\url{http://www.anes.uab.edu/})}
\end{minipage}
\end{center}

\bigskip

It has long been an important problem in medical science to devise some 
 method of mitigating the pain of surgical operations. An efficient 
 agent for this purpose has at length been discovered. A patient has been rendered 
        completely insensible during an amputation of the thigh, regaining 
consciousness after a short interval. Other severe operations have been 
      performed without the knowledge of the patients. So remarkable an
 occurrence will, it is believed, render the following details relating to 
      the history  and character of the process, not uninteresting. 
        

        On the 16th of Oct., 1846, an operation was performed at the hospital 
        upon a patient who had inhaled a preparation administered by 
    Dr.\ Morton, a dentist of this city, with the alleged intention of producing 
      insensibility to  pain. Dr.\ Morton was understood to have extracted 
teeth under similar  circumstances, without the knowledge of the patient. The present operation  was performed by Dr.\ Warren, and though comparatively slight, involved  an incision near the lower jaw of some inches in extent. During the 
      operation the patient muttered, as in a semi-conscious state, and afterwards 
      stated that the pain was considerable, though mitigated; in his own words, 
      as  though the skin had been scratched with a hoe. There was, probably, in 
      this instance, some defect in the process of inhalation, for on the 
      following day the vapor was administered to another patient with complete success. 
A fatty tumor of considerable size was removed, by Dr.\ Hayward, from the arm 
        of a woman near the deltoid muscle. The operation lasted four or five 
      minutes, during which time the patient betrayed occasional marks of 
      uneasiness;  but upon subsequently regaining her consciousness, professed not only to   have felt no pain, but to have been insensible to surrounding objects, 
      to   have known nothing of the operation, being only uneasy about a child 
      left  at home. No doubt, I think, existed, in the minds of those who saw this 
      operation, that the unconsciousness was real; nor could the imagination 
      be  accused of any share in the production of these remarkable phenomena. 
        

        I subsequently undertook a number of experiments, with the view of 
        ascertaining the nature of this new agent, and shall briefly state them, 
      and  also give some notice of the previous knowledge which existed of the 
      use of the substances I employed. 
        
        The first experiment was with sulphuric ether, the odor of which was 
        readily recognized in the preparation employed by Dr.\ Morton. Ether inhaled in vapor is well known to produce symptoms similar to those produced by the nitrous oxide. In my own former experience the exhilaration 
        has been quite as great, though perhaps less pleasurable, than that of 
      this  gas, or of the Egyptian haschish. It seemed probable that the ether 
      might  be so long inhaled as to produce excessive inebriation and 
      insensibility; but   in several experiments the exhilaration was so considerable that the 
      subject 
        became uncontrollable, and refused to inspire through the apparatus. 
      Experiments were next made with the oil of wine (ethereal oil). This is 
      well 
        known to be an ingredient in the preparation known as Hoffman's 
      anodyne, 
        which also contains alcohol, and this was accordingly employed. Its 
      effects 
        upon the three or four subjects who tried it, were singularly opposite 
      to 
        those of the ether alone. The patient was tranquillized, and generally 
      lost 
        all inclination to speak or move. Sensation was partially paralyzed, 
      though 
        it was remarkable that consciousness was always clear, the patient 
      desiring 
        to be pricked or pinched, with a view to ascertain how far sensibility 
      was 
        lost. A much larger proportion of oil of wine, and also chloric ether, 
      with 
        and without alcohol, were tried, with no better effect. 
    
    
        It may be interesting to know how far medical inhalation has been 
       previously employed. Medicated inhalation has been often directed to the 
        amelioration of various pulmonary affections, with indifferent success. 
      Instruments called Inhalers were employed long ago by Mudge, Gairdner and 
        Darwin, and the apparatus fitted up by Dr.\ Beddoes and Mr.\ James Watt, 
        for respiring various gases, has given birth to some octavo volumes. 
      More 
        recently Sir Charles Scudamore has advocated the inhalation of iodine 
      and 
        conium in phthisis, and the vapor of tar has been often inhaled in the 
      same 
        disease. The effects of stramonium, thus administered, have been 
      noticed by  Sigmond. 
        
        The inhalation of the ethers has been recommended in various maladies, 
        among which may be mentioned phthisis and asthma. ``On sait que la 
        respiration de 1'ether sulfurique calme souvent les accidents nerveux 
      de  certains croups,''  is from the \textit{Dict.\ des Sc.\ Med.}; but I find that 
      mention of the inhalation of this agent is usually coupled with a caution against 
      its 
        abuse, grounded apparently upon two or three cases, quoted and 
      requoted. 
        Of these the first is from Brande's Journal of Science, where it is 
      thus reported: ``By imprudent respiration of sulphuric ether, a gentleman was 
        thrown into a very lethargic state which continued from one to three 
      hours, 
        with occasional intermissions and great depression of spirits --- the 
      pulse being 
        for many days so low that considerable fears were entertained for his 
      life.''
        Christison quotes the following from the \textit{Midland Med.\ and Surg.\ 
      Journal},  to prove that nitric ether in vapor is a dangerous poison when too 
      freely and 
        too long inhaled: ``A druggist's maid servant was found one morning dead 
      in 
        bed, and death had evidently arisen from the air of her apartment 
      having 
        been accidentally loaded with vapor of nitric ether, from the breaking 
      of 
        a three gallon jar of the Spiritus AEth. Nitric. She was found lying on 
      her 
        side, with her arms folded across her chest, the countenance and 
      posture 
        composed, and the whole appearance like a person in a deep sleep. The 
        stomach was red internally, and the lungs were gorged.'' 
     The editor of  the 
        journal where this case is related, says he is acquainted with a 
      similar instance, where a young man was found completely insensible from 
      breathing 
        air loaded with sulphuric ether, remained apoplectic for some hours, 
      and 
        would undoubtedly have perished had he not been discovered and removed 
        in time. Ether is now very commonly administered internally as a 
      diffusible 
        stimulant and antispasmodic, in a dose of one or two drachms. But here 
      also 
        we have the evidence of a few experiments that ether is capable of 
      producing grave results under certain circumstances. Orfila killed a dog by 
      confining a small quantity in the stomach by means of a ligature around 
      the 
        oesophagus. Jager found that 3 xxi.\ acted as a fatal poison to a crane. 
      It was 
        for a long time supposed to be injurious to the animal economy. The old 
        Edinburgh Dispensatory, republished here in 1816, explicitly states 
      that it 
        is to be inhaled by holding in the mouth a piece of sugar, containing a 
      few 
        drops, and also that regular practitioners give only a few drops for a 
      dose; 
        ``though,'' it adds, ``empirics have sometimes ventured upon much larger 
        quantities, and with incredible benefit'' p.~566. Nevertheless it was 
      known to 
        have been taken in correspondingly large doses with impunity. The 
      chemist 
        Bucquet, who died of scirrhus of the colon, with inflammation of the 
      stomach and intestines, took before his death a pint of ether daily, to 
      alleviate 
        his excruciating pains (he also took 100 gr.\ opium daily); --- and 
      Christison   mentions an old gentleman who consumed for many years q xvi every eight 
        or ten days. Such facts probably led Merat and Le Lens, in their 
      Matiere 
        Medicale, to question its grave effects when swallowed. Mentioning the 
        case of Bucquet, they say, even of its inhalation, that it produces 
      only ``on  sentiment de fraicheur que suit bientot une legere excitation.''
        

        This variety of evidence tends to show that the knowledge of its 
      effects, 
        especially those of its inhalation, was of uncertain character. Anthony 
      Todd 
        Thomson well sums up what I conceive to have been the state of 
      knowledge 
        at the time upon this subject, in his London Dispensatory of 1818. ``As 
      an 
        antispasmodic, it relieves the paroxysm of spasmodic asthma, whether it 
      be 
        taken into the stomach, or its vapor only be inhaled into the lungs. 
      Much 
        caution, however, is required in inhaling the vapor of ether, as the 
      imprudent inspiration of it has produced lethargic and apoplectic 
      symptoms.''
        In his Materia Medica and Therapeutics, of 1832, however, omitting all 
        mention of inhalation, he uses the following words: ``Like other 
      diffusible 
        excitants, its effects are rapidly propagated over the system, and soon 
      dissipated. From its volatile nature its exciting influence is probably 
      augmented; 
        as it produces distension of the stomach and bowels, and is thus 
      applied to 
        every portion of their sensitive surface. It is also probable that it 
      is absorbed in its state of vapor, and is therefore directly applied to the 
      nervous 
        centres. It is the diffusible nature of the stimulus of ether which 
      renders 
        it so well adapted for causing sudden excitement, and producing 
      immediate 
        results. Its effects, however, so soon disappear, that the dose 
      requires to 
        be frequently repeated.''

        
        Nothing is here said of inhalation, and we may fairly infer that the 
      procedure 
        had so fallen into disrepute, or was deemed to be attended with such 
      danger, as to render a notice of it superfluous in a work treating, in 
      1832, of  therapeutics. 
        
        It remains briefly to describe the process of inhalation by the new 
      method 
        and to state some of its effects. A small two-necked glass globe 
      contains the 
        prepared vapor, together with sponges to enlarge the evaporating 
      surface. 
        One aperture admits the air to the interior of the globe, whence, 
      charged 
        with vapor, it is drawn through the second into the lungs. The inspired 
      air 
        thus passes through the bottle, but the expiration is diverted by a 
      valve in 
        the mouth piece, and escaping into the apartment is thus prevented from 
        vitiating the medicated vapor. A few of the operations in dentistry, in 
      which 
        the preparation has as yet been chiefly applied, have come under my 
       observation. The remarks of the patients will convey an idea of their 
      sensations. 
        
        A boy of sixteen, of medium stature and strength, was seated in the 
      chair. 
        The first few inhalations occasioned a quick cough, which afterwards 
      subsided; at the end of eight minutes the head fell back, and the arms 
      dropped 
        but owing to some resistance in opening the mouth, the tooth could not 
      be  reached before he awoke. He again inhaled for two minutes, and slept 
      three  minutes, during which time the tooth, an inferior molar, was extracted. 
      At  the moment of extraction the features assumed an expression of pain, 
      and  the hand was raised. Upon coming to himself he said he had had a ``first 
        rate dream -- very quiet," he said, "and had dreamed of Napoleon -- had 
      not 
        the slightest consciousness of pain -- the time had seemed long;'' and 
      he left 
        the chair, feeling no uneasiness of any kind, and evidently in a high 
      state of 
        admiration. The pupils were dilated during the state of 
      unconsciousness, and   the pulse rose from 130 to 142. 
        
        A girl of sixteen immediately occupied the chair. After coughing a 
      little, she inhaled during three minutes, and fell asleep, when a molar tooth 
      was  extracted, after which she continued to slumber tranquilly during three 
        minutes more. At the moment when force was applied she flinched and 
        frowned, raising her hand to her mouth, but said she had been dreaming 
        a pleasant dream and knew nothing of the operation. 
        
        A stout boy of twelve, at the first inspiration coughed considerably, 
      and 
        required a good deal of encouragement to induce him to go on. At the 
      end 
        of three minutes from the first fair inhalation, the muscles were 
      relaxed and 
        the pupil dilated. During the attempt to force open the mouth he 
      recovered 
        his consciousness, and again inhaled during two minutes, and in the 
      ensuing 
        one minute two teeth were extracted, the patient seeming somewhat 
     conscious, but upon actually awaking he declared  ``it was the best fun he 
      ever  saw,'' avowed his intention to come there again, and insisted upon 
      having 
        another tooth extracted upon the spot. A splinter which had been left, 
      afforded an opportunity of complying with his wish, but the pain proved 
      to 
        be considerable. Pulse at first 110, during sleep 96, afterwards 144; 
      pupils  dilated. 
        
        The next patient was a healthy-looking, middle-aged woman, who inhaled 
        the vapor for four minutes; in the course of the next two minutes a 
      back 
        tooth was extracted, and the patient continued smiling in her sleep for 
      three 
        minutes more. Pulse 120, not affected at the moment of the operation, 
      but 
        smaller during sleep. Upon coming to herself, she exclaimed that ``it 
      was 
        beautiful --- she dreamed of being at home --- it seemed as if she had 
      been gone 
        a month.'' These cases, which occurred successively in about an hour, at 
      the  room of Dr.\ Morton, are fair examples of the average results produced 
      by 
        the inhalation of the vapor, and will convey an idea of the feelings 
      and expressions of many of the patients subjected to the process. Dr.\ Morton 
      states   that in upwards of two hundred patients, similar effects have been
     produced. The inhalation, after the first irritation has subsided, is 
      easy, and produces a complete unconsciousness at the expiration of a 
      period  varying  from  two to five or six, sometimes eight minutes; its duration        varying from two to five minutes; during which the patient is completely insensible to the  ordinary tests of pain. The pupils in the cases I have observed have 
      been  generally dilated; but with allowance for excitement and other 
      disturbing  influences, the pulse is not affected, at least in frequency; the 
      patient remains in a calm and tranquil slumber, and wakes with a pleasurable 
      feeling. 
        The manifestation of consciousness or resistance I at first attributed 
      to the  reflex function, but I have since had cause to modify this view. 
        
        It is natural to in quire whether no accidents have attended the 
     employment of a method so wide in its application, and so striking in its 
      results. I  have been unable to learn that any serious consequences have ensued. 
      One  or two robust patients have failed to be affected. I may mention as an 
      early  and unsuccessful case, its administration in an operation performed by 
      Dr.\ Hayward, where an elderly woman was made to inhale the vapor for at 
        least half an hour without effect. Though I was unable at the time to 
      detect 
        any imperfection in the process, I am inclined to believe that such 
      existed. 
        One woman became much excited, and required to be confined to the 
      chair. 
        As this occurred to the same patient twice, and in no other case as far 
      as I 
        have been able to learn, it was evidently owing to a peculiar 
      susceptibility. 
        Very young subjects are affected with nausea and vomiting, and for this 
        reason Dr.\ M.\ has refused to administer it to children. Finally, in a 
      few 
        cases, the patient has continued to sleep tranquilly for eight or ten 
      minutes, 
        and once, after a protracted inhalation, for the period of an hour. 
        
        The following case, which occurred a few days since, will illustrate 
      the   probable character of future accidents. A young man was made to inhale 
        the vapor, while an operation of limited extent, but somewhat 
      protracted 
        duration, was performed by Dr.\ Dix upon the tissues near the eye. After 
      a 
        good deal of coughing the patient succeeded in inhaling the vapor, and 
      fell 
        asleep at the end of about ten minutes. During the succeeding two 
      minutes 
        the first incision was made, and the patient awoke, but unconscious of 
      pain. 
        Desiring to be again inebriated, the tube was placed in his mouth and 
      retained there about twenty-five minutes, the patient being apparently 
      half 
        affected, but, as he subsequently stated, unconscious. Respiration was 
      performed partly through the tube and partly with the mouth open. 
     Thirty-five minutes had now elapsed, when I found the pulse suddenly 
      diminishing 
        in force, so much so, that I suggested the propriety of desisting. The 
      pulse 
        continued decreasing in force, and from 120 had fallen to 96. The 
      respiration was very slow, the hands cold, and the patient insensible. 
      Attention was 
        now of course directed to the return of respiration and circulation. 
      Cold 
        allusions, as directed for poisoning with alcohol, were applied to the 
      head, 
        the ears were syringed, and ammonia presented to the nostrils and 
      administered internally. For fifteen minutes the symptoms remained 
      stationary, 
        when it was proposed to use active exercise, as in a case of narcotism 
      from 
        opium. Being lifted to his feet, the patient soon made an effort to 
      move his 
        limbs, and the pulse became more full, but again decreased in the 
      sitting 
        posture, and it was only after being compelled to walk during half an 
      hour 
        that the patient was able to lift his head. Complete consciousness 
      returned 
        only at the expiration of an hour. In this case the blood was flowing 
      from 
        the head, and rendered additional loss of blood unnecessary. Indeed the 
        probable hemorrhage was previously relied on as salutary in its 
      tendency. 
        
        Two recent cases serve to confirm, and one I think to decide, the great 
        utility of this process. On Saturday, the 7th Nov., at the Mass. 
      General 
        Hospital, the right leg of a young girl was amputated above the knee, 
      by 
        Dr.\ Hayward, for disease of this joint. Being made to inhale the 
      preparation, 
        after protesting her inability to do so from the pungency of the vapor, 
      she 
        became insensible in about five minutes. The last circumstance she was 
      able 
        to recall was the adjustment of the mouth piece of the apparatus, after 
      which 
        she was unconscious until she heard some remark at the time of securing 
        the vessels -- one of the last steps of the operation. Of the incision 
      she knew 
        nothing, and was unable to say, upon my asking her, whether or not the 
        limb had been removed. She refused to answer several questions during 
      the 
        operation, and was evidently completely insensible to pain or other 
      external 
        influences. This operation was followed by another, consisting of the 
      removal of a part of the lower jaw, by Dr.\ Warren. The patient was 
      insensible to 
        pain of the first incision, though she recovered her consciousness in 
      the  course of a few minutes. 
        
        The character of the lethargic state, which follows this inhalation, is 
      peculiar. The patient loses his individuality and awakes after a certain 
      period, 
        either entirely unconscious of what has taken place, or retaining only 
      a faint 
        recollection of it. Severe pain is sometimes remembered as being of a 
      dull 
        character; sometimes the operation is supposed by the patient to be 
      performed upon somebody else. Certain patients, whose teeth have been extracted, remember the application of the extracting instruments; yet 
      none  have been conscious of any real pain. 
        
        As before remarked, the phenomena of the lethargic state are not such 
      as 
        to lead the observer to infer this insensibility. Almost all patients 
      under the 
        dentist's hands scowl or frown; some raise the hand. The patient whose 
      leg 
        was amputated, uttered a cry when the sciatic nerve was divided. Many 
      patients open the mouth, or raise themselves in the chair, upon being 
      directed 
        to do so. Others manifest the activity of certain intellectual 
      faculties. An 
        Irishman objected to the pain, that he had been promised an exemption 
      from 
        it. A young man taking his seat in the chair and inhaling a short time, 
      rejected the globe, and taking from his pockets a pencil and card wrote 
      and 
        added figures. Dr.\ M.\ supposing him to be affected, asked if he would 
      now 
        submit to the operation, to which the young man willingly assented. A 
      tooth 
        was accordingly extracted, and the patient soon after recovered his 
      senses. 
        In none of these cases had the patients any knowledge of what had been 
        done during their sleep. 
        
        I am, as yet, unable to generalize certain other symptoms to which I 
      have 
        directed attention. * The pulse has been, as far as my observation 
      extends, 
        unaltered in frequency, though somewhat diminished in volume, but the 
        excitement preceding an operation, has, in almost every instance, so 
      accelerated the pulse that it has continued rapid for a length of time. 
      The 
        pupils are in a majority of cases dilated; yet they are in certain 
      cases unaltered, as in the above case of amputation. 
        
        The duration of the insensibility is another important element in the 
        process. When the apparatus is withdrawn at the moment of 
       unconsciousness, it continues, upon the average, two or three minutes, and the 
      patient 
        then recovers completely or incompletely, without subsequent ill 
      effects. In 
        this sudden cessation of the symptoms, this vapor in the air tubes 
      differs in 
        its effects from the narcotics or stimulants in the stomach, and, as 
      far as the 
        evidence of a few experiments of Dr.\ Morton goes, from the ethereal 
      solution 
        of opium when breathed. Lassitude, headache and other symptoms lasted 
        for several hours, when this agent was employed. 
        

        But if the respiration of the vapor be prolonged much beyond the first 
        period, the symptoms are more permanent in their character. In one of 
      the 
        first cases, that of a young boy, the inhalation was continued during 
      the 
        greater part of ten minutes, and the subsequent narcotism and 
      drowsiness 
        lasted more than an hour. In a case alluded to before, the narcotism 
      was 
        complete during more than twenty minutes, the insensibility approached 
      to  coma. 
        
        Such cases resemble those before quoted from Christison and other 
        authors, and show that the cessation of the inhalation, after it has 
      been 
        prolonged for a length of time, does not produce a corresponding 
      cessation 
        of the symptoms; while, if the inhalation is brief, the insensibility 
      ceases in 
        a short time. Recovery, in the latter case, is not improbably due to 
      the 
        complete and rapid elimination of the vapor from the lungs; the more 
        gradual return of consciousness, in the former case, to the presence of 
      a larger quantity of unexhaled particles. A fact mentioned by Christison 
      bears 
        upon this point. This author states that insensibility from the 
      presence of a 
        large quantity of alcohol in the stomach, often gives place to a 
      complete 
        and sudden return of consciousness, when the alcohol is removed by the 
        stomach pump. It is probable that the vapor of the new preparation 
      ceases 
        early to act upon the system, from the facility with which it is 
      exhaled. 
       
 
        The process is obviously adapted to operations which are brief in their 
        duration, whatever be their severity. Of these, the two most striking 
      are, 
        perhaps, amputations and the extraction of teeth. In protracted 
      dissections, 
        the pain of the first incision alone is of sufficient importance to 
      induce its 
        use; and it may hereafter prove safe to administer it for a length of 
      time, 
        and to produce a narcotism of an hour's duration. It is not unlikely to 
      be 
        applicable in cases requiring a suspension of-muscular action; such as 
      the 
        reduction of dislocations or of strangulated hernia: and finally it may 
      be 
        employed in the alleviation of functional pain, of muscular spasm, as 
      in 
        cramp and colic, and as a sedative or narcotic. 
        
        The application of the process to the performance of surgical 
      operations, 
        is, it will be conceded, new. If it can be shown to have been 
      occasionally 
        resorted to before, it was only an ignorance of its universal 
      application and 
        immense practical utility that prevented such isolated facts from being 
        generalized. 
        
        It is natural to inquire with whom this invention originated. Without 
        entering into details, I learn that the patent bears the name of
       Dr.\ Charles  T.\ Jackson, a distinguished chemist, and of Dr.\ Morton, 
     a skilful  dentist, of 
        this city as inventors --- and has been issued to the latter gentleman 
      as  proprietor. 
        
        It has been considered desirable by the interested parties that the 
      character of the agent employed by them, should not be at this time 
      announced; 
        but it may be stated that it has been made known to those gentlemen who 
        have had occasion to avail themselves of it. 
        I will add, in conclusion, a few remarks upon the actual position of 
      this  invention as regards the public. 
        
        No one will deny that he who benefits the world should receive from it 
      an 
        equivalent. The only question is, of what nature shall the equivalent 
      be? 
        Shall it be voluntarily ceded by the world, or levied upon it? For 
      various 
        reasons, discoveries in high science have been usually rewarded 
      indirectly 
        by fame, honor, position, and occasionally, in other countries, by 
      funds 
        appropriated for the purpose. Discoveries in medical science, whose 
      domain 
        approaches so nearly that of philanthropy, have been generally ranked 
      with 
        them; and many will assent with reluctance to the propriety of 
      restricting 
        by letters patent the use of an agent capable of mitigating human 
      suffering. 
        There are various reasons, however, which apologize for the arrangement 
        which I understand to have been made with regard to the application of 
      the 
        new agent. 
        

        1st. It is capable of abuse, and can readily be applied to nefarious 
      ends. 
        
        2nd. Its action is not yet thoroughly understood, and its use should be 
        restricted to responsible persons. 
        
        3d. One of its greatest fields is the mechanical art of dentistry, many 
      of 
        whose processes are by convention, secret, or protected by patent 
      rights. 
        
        It is especially with reference to this art, that the patent has been 
      secured. 
        We understand, already, that the proprietor has ceded its use to the 
      Mass. 
        General Hospital, and that his intentions are extremely liberal with 
      regard 
        to the medical profession generally, and that as soon as necessary 
      arrangements can be made for publicity of the process, great facilities will 
      be 
        offered to those who are disposed to avail themselves of what now 
      promises 
        to be one of the important discoveries of the age. 
        
        
        * Since the above was written, I find this irregularity of symptoms 
      mentioned in 
        of poisoning by alcohol. Dr.\ Ogston, according to Christison, has in 
      vain attemp 
        together and to classify the states of respiration, pulse, and pupil.

\begin{center}
-----------
\end{center}

\end{document}
