V / w\ . THE EFFECT OF ANESTHETICS UPON THE HUMAN SYSTEM, AS EVIDENCED BY SPECTROSCOPIC ■ OBSERVATIONS. Read at a meeting of the American Dental Convention, the Southern Dental Association and the Dental Society,of ike State of Maryland, and District of Columbia, irt ^j'tftnt'session at Oakland, Maryland, August 16, 1877. \M 1,", ^_ BY DR. S. WATERMAN, OF NEW YORk><' • f{ * ~l VV . Mr. President, Officers and Members of the Convention, Ladies and Gentlemen: There is probably no difference of opinion in the profession, that a perfect anaesthetic, one possessing all the requisite properties to insure rapid action, complete safety, freedom from pernicious after effects, combined with cheapness and readiness in its prep- aration, would be one of the greatest boons to suffering humanity. And I am also certain that there exists no difference of opinion amongst us to-day, that we do not, as yet, possess this boon; that none of the anaesthetics known to us at present, possess 2 all these priceless properties, and that, in dealing with these subtle agents, we are, indeed, passing the border land which separates life from death. I think it must be conceded that all anaesthetical agents now employed are more or less dangerous to health and life, and their employment is beset with more or less grave consequences. For estimating the effects of an anaes- thetic upon the human system, its mode of action should be critically known before hand, not empirically only; we should be able to foretell what the action of a certain agent would be upon a given individual, by closely examining into the physical condition; and we should be fully able to appreciate jK/ patho- logical states that forbid or modify its exhibition. To this end every rational practitioner is bound to understand the chemical / composition of these wonderful agents, and, above all, what particular organ or fluid in the human economy is primarily effected by them; and also the precise manner of the changes which take place in the same. Those who imagine that all anaesthetics act upon the animal economy alike, and their peculiar mode of action is the same under all circumstances, have yet to learn that this is far from being the case; that on the contrary, various agents effect the system in quite different ways. This knowledge, pregnant with the utmost importance, has become almost positive through the agency of the spectroscope. It has supplied the missing link to our chain of reasoning; the shadowy field of theories has been cleared up; the laws govern- ing the relations of anaesthetics, in contact with the blood current, have been ascertained, and rational progress has been made to insure safe anaesthetics. I have abiding faith in the progress of chemical science, that it will finally point out an agent from the almost inexhaustable material at its command, that will satisfy all ends of surgical requirements ; an anaesthetic that, whilst it will annihilate, temporarily all sensation, will leave consciousness and vitality intact. We are the more entitled to entertain this hope, as we are already acquainted with some agents, that, when locally employed, suspend the sensibility of the parts. Rhigolene ^^ is one of them, otherwise known as byHn^ r.f p^nfyi ^r -\\x\y\ (/&^n /^*i ■ a light fragrant fluid, the boiling point of which is 86° F. In the s* // trimethylic ether we possess another remarkable agent of this s£7di? t & /// 3 class. Much of the knowledge we possess on these subjects has been supplied by the English savant, Dr. Richardson. I have clipped the following passage from his report of 1870 : "In a previous report on amyl/ne, I pointed out that its vapor, whilst it destroys sensation, does not destroy all conscious acts; and in my later observations on the action of methylic ether, C.7 H. 16, O3, the same facts have been more perfectly elicited. In several cases where I administered this ether, for removing pain in surgical operations, the patients, when quite insensible to pain, were so conscious that they were able to obey every request made of them, and in some instances were anxious to reason, stating that they knew what was going on, and arguing that they were not ready for the operation because they were sure they would feel pain. Nevertheless, in this state of mental activity, they were operated on, and afterwards, while remembering every incident, were firm in their assertion that they felt no pain what- ever during the operation. One patient, who sat for the extrac- tion of two teeth, selected the tooth to be first extracted, putting her finger on it, and afterwards re-arranging her position for the second removal. To the looker on, it seemed, in fact, as though no change in her life had occurred, yet she affirmed that she was sensible of no pain whatever; and several other less striking, but hardly less singular examples, came before me. "We may, then, I think, fairly assume, that, in course of time, we shall discover, manageable and certain anaesthetic substances which will paralyze sensation only, leaving the muscular power unaltered, and the mental little disturbed; and we gather from this that either in the cerebral hemisphere there is some distinct and simple center of common sensation, which may be acted upon by certain agents without involving all the cerebral mass, or that the peripheral nervous matter may be influenced without involving those portions of the nervous system." What Dr. Richardson here says is of the utmost importance on the subject before us. There may be cases where it may be useful, nay, necessary to suspend consciousness also, and we should be able to graduate our agent in a manner so as to push onward, to any desirable degree, without endangering the life of our patients. 4 Those who desire to learn more of this subject are referred to Dr. Richardson's most able and exhaustive report; and also to the highly interesting and admirable lecture by Prof. B. Silliman, Jr., of Yale, delivered to the medical class in Yale College, September 14th, 1871, and afterwards printed in pamphlet form, and in the American Journal of Science and Art. I have already referred to the spectroscope, and told you that the spectral analytical test gives us most valuable information upon the subject before us. I propose now to make this assertion good. There may be many amongst my kind hearers that know all about the spectroscope, and the work it can do and has done for chemistry and celestial and terrestial physics Others/ perhaps, may have given the subject less attention. For the/benefit of all and in order to give a clear and satisfactory view, I shall speak as if this interesting subject was entirely new to you. And in the first place, what is meant by the term "spectral analysis ? " It is a scientific process in which solar or artificial light is em- ployed, in connection with a series of prisms, to analyze organic as well as inorganic substances. The instrument employed for this purpose is called a spectroscope, and when connected to a microscope we call it a micro-spectroscope. It consists of a num- ber of prismswithin telescopic tubes, and a slit arrangment so as to regulate the admission of light,and one or more collimator lenses to gather the rays and make them parallel. Through the mo\ a- ble slit the light enters and passes through the prism or prisms, and through one of the telescopic tubes the colored image or spectrum passes into the observer's eye, and is appreciated by the retina. This image may also be thrown upon a white screen, a method that I would gladly resort to had I possession of the necessary screen arrangements. You all know what happens when a ray of white light passes through a prism. It is decomposed into its ultimate constituent colored tints, forming a beautiful band called a spectrum. It contains all the colors of the rainbow, in regular succession of tints from red to orange yellow, green, blue and violet. We witness, also, other inter- esting changes. When white light passes through a prism, the emerging rays are seen to have been bent out of their course. 5 They spread fan-like to the left and to the right. They are dis- persed, and we call it the refraction of rays. The violet part of the spectrum is greatly more bent out of its course than the red part, which is less refrangible. This deflection and greater refrangibility of the violet rays, depends upon the constitution and nature of light itself, whose waves are propagated through space by a subtle fluid known as the " luminiferous ether, which fills the illimitable space and permeates every atom of matter. These etherial waves differ in length, the longest form the ex- treme red part of the visible spectrum, the shortest those of the extreme violet. According to Tyndal, the length of an etherial wave of the extreme red wouldrequire 36,918 placed end to end to cover one inch, whilst the extreme violet requires 64,631 to the inch." As the sun's light comes to us from a distance of 90,000,000 of miles, we can perceive the amazing number of waves and their inconceivable velocity, considering that these waves reach us in the short time of 8j4 minutes. The number of ether impulses necessary to produce upon our retina the im- pression of red light, is, therefore, 451 billions per second, and in order to produce the impression of extreme violet, 789 billions are required. Impulses above, as well as below these numbers fail to make any impression upon our retina. This, is indeed, a captivating chapter of physics, but I am admonished that my subject lies in a different direction, to which I am in duty bound to return. When the light we employ for analytical purposes is artificial, say the flame of an oil or petroleum lamp, of the magnesium or electric arc light, we see the tints pass imperceptably, one into the other, and we have what is called an uninterrupted spec- trum. When, however, sun-light is used, or the light from any planet that reflects the solar light, say the light of the moon, we find that the spectral band is traversed by thousands of fine lines, some darker and broader than others; such a spectrum is called an interrupted or solar spectrum. The inquiry into the cause of these solar lines is full of inter- est, but I have neither time nor space to enter fully into its con- sideration. 6 These captivating features of spectral analysis are applicable to solar and celestial phjsics, but are not absolutely necessary to the intense, logical inquiry before us. The lines which traverse the solar spectrum are constant, and never change position. They have been mapped by Thalen and Angstrcem and Kirch- hoff. Rutherford, of New York, has photographed a portion of them from the sun itself. Fraunhofer employed the most prominent of these lines for purposes of measurement as far back as 1814. He selected 9 lines in various parts of the spectrum and named them A, B, C, D, E, F^jG^H and hf and £/ ^t/~t these lines are known the world over as Fraunhofer's lines. / • / You will understand by and by how useful these lines are in spectral analysis. These 9 lines, and in fact every one of the thousands of lines that traverse the spectrum, represent some terrestrial substance in a vaporous condition in the sun; and we learn from those hieroglyphic lines, that the sun, the stars, the comets and the nebulae, the aurora borealis and the zodiacal light, which, according to the latest view, encircle our earth as y Saturn is encircled by a triple set of rings, that in short, all celestial bodies, without exception, contain substances or ele- ments which we meet on our earth, thus bearing witness to the unity of the Universe. The D, line is produced by burning sodium; the lines C, F, and G, are peculiar to burning hydrogen gas; the E, line is one of the most prominent iron lines; the line H, is produced by the A? vapors of magnesium, and the H, line is characteristic of vola- talized calcium. In our inquiries these lines serve us as land- marks* to register the position ofbrightlines and absorption bands. Scales, graduated into tens and hundreds of degrees, are also em- ployed and placed above the spectra dividing the color regions. The process of making an analysis by means of the spec- troscope is simple indeed. Bodies to be examined are either solids, liquids or gases. The solids are volatilized by means of heat. To this end we employ a Bunsen's burner, the electric arc, or the compound oxygen fltme. Fluids are placed before the slit of the spectroscope in suita- ble glass vessels, with plane parallel walls. When the rays of light pass through colored solutions, ere they impinge upon the 7 prism, various tints are absorbed. We observe a variety of dark bands, varying in shades, in numbers, and in position in the spectral regions. There are no two substances/ at present known, that give absolutely the same bands. / ~" ~~ X^ Gases are examined by means of tubes devised by Pflucker & Geisler and known as Geisler's tubes. They are made of various sizes and shapes, some quite fanciful. They consists of theif-1^* thermometer/ tubes with a bulb at each extremity, into which electrodes of platinum or aluminum are soldered. Electrodes of other metals would oxidize in the extreme heat generated. The tubes are filled with the gas we wish to experiment upon. The air pump is then applied until the 1-600 or 1-700 part of the ordinary atmospheric pressure is left. Then we pass/n electric ^ spark through the attenuated gas, which in this condition, no longer resists the passage of the spark; intense heat is generated, and brilliant and beautiful lights emitted, of various colors, changing of course with the different gases employed. Being able then to master the solids, fluids, and gases, no known substance can escape the analytical powrer of the spec- troscope. Every known substance modifies the spectrum in a manner specific or peculiar to itself. Some substances give only bright lines, for example the glowing gases, others give dark lines and absorption bands. Some absorb all the colors of the spectrum with the exception of a single bright line. Ob- serve, in the subjoined diagram, the spectra of sodium and thal- lium. Others give a spectrum of many bright lines; compare the spectra of barium, caesium, and rubidium. It does seem at first sight, that the immense variety of lines and bands would lead us into inextricable confusion. A little prac- tice will dispel this illusion however. We soon become famil- iar with these landmarks. The variety of the spectra, the rel- ative position of bands and lines, their peculiar forms and outlines, difference in brightness, depth of shading of bands and their number in each instance, are characteristic enough to insure ready recognition, even by persons not accustomed to work with the spectroscope. 8 DELICACY OF THE SPECTRUM OR PRISMATIC TEST. Let me say a few words regarding the extraordinary delicacy of the spectrum test, which far surpasses every other test known to us. The following example is supplied by Dr. Schollin: "Let us divide one pound of common table salt, the sodium chloride into 500,000 equal parts. One of these minute dust particles is called a milligram. The experienced chemist is able to weigh such a minute particle only with the most delicate' scales and with extraordinary care and acquired dexterity, but with this performance he has arrived at the limit of possibilities. And now ask the chemist to divide this milligram into further 3,000,000 equal parts, and he will shrink appalled from the performance of this impossi- ble task. The human mind cannot conceive of an object so exceedingly minute. Yet we can demonstrate the presence of such an infinitesimal quantity of sodium chloride by the spectral test. You know that this salt is ever present in nature in extremely fine division. Its never failing source is the sea; fine particles of it are supplied to the air by the action of winds and storms and by the slower processes of evaporation, thus sup- plying one of the most absolutely necessary elements to life in its manifold forms and conditions, and furnishing one of the most powerful antiseptics, whereby contamination of air, earth and water is prevented. The dusting, or slapping together of dusty books in the re- motest corner of this hall will immediately produce a yellow flash in a burning candle or gas flame at this end, which when examined with the spectroscope will show most distinctly the yellow line in D, which, as you have already been informed is the sodium line. There is another very peculiar and highly useful characteris- tic of the prismatic test, to which I desire to direct your attention. You can examine a number of spectra at one and the same time, that is, you can analyze a number of substances at the same time. Take, for instance, the ash obtained from the incineration of human, or animal tissues. The hydro-chlorate solution of this ash gives a splendid spectrum, the field of which show? 9 /7 / many red, yellow, green and blue lines in various regions of a dark spectral ground. (*) By careful comparison we find that these lines belong to six metals, to-wit: potassium, sodium, lithium, rubidium, caesium, and calcium. We can give another striking example. The ashed end of a cigar, moistened with hydro-chloric acid and held in the flame of a Bunsen's burner, yields the lines of sodium, potassium, lithium, caesium, rubidium, calcium.—(Thudicuiris report to the privy council, 1876.) Four new metals were discovered by means of the spectroscope, of very great interest to science, which would otherwise, most probably, have never been known to us. Burden and Kirchhoff •, discovered, in the waters of Durckheim, caesium and rubidium/ Q J —for, boiling down forty tuns of its mineral waters, they found 200 ' grains of the mixed salts of the above metals, and by the marvelous analytical powers of the spectroscope, indentified these substances. (i860.) Since then these metals have been found in many other localities, especially rubidium, to which many of the most cele- brated springs in Europe owe part of their curative powers. . Thallium, a most important metal, was discovered by Crooky^/ in 1861, in some of the iron pyrites and in a seleniferous deposit 7 from a sulphuric acid factory, at Telkerode, in the Hartz. (Roscoe.) Reich and Richter discovered, in the same way, the red metal indium, (1864) on account of its spectrum, two indigo- blue lines. You may rightly conjecture that an instrument possessing such wonderful analytical powers, must have found application in manufactures, arts and sciences; its influence upon celestial chem- istry is simply stupendous ; it has completely revolutionized our views in this direction. A comparison of the dark lines of the sun, and its planets, with those of Sirius, and other fixed stars, shows us, that the same substances known to us are present in all these. Differently arranged as those lines are in different stars, many of them are sufficiently coincident to establish their indentity. When we come to examine the irresolvable nebulous mass, we obtain no longer dark lines, but bright lines only; and we learn thereby, that these bodies consist of burning gases, *See diagram. IO principally hydrogen, which is also so abundant in the sun, when, during the fire storms raging there, it is carried up with explo- sive force, many hundred thousand miles, in the shape of fiery columns. As we come down to the still lower grade of cosmic evolution, to the nebulous mass, even these bright lines diminish in number, until but a few of them remain visible. One line in F. seems to be always present, the line is nearly coincident with the hy- drogen line; another seems to indicate the presence of nitrogen, and still another has not as yet been identified. In the comets all the bright lines have disappeared. Faintly illuminated spots mark the place where, in ages to come, bright lines will appear. These spots correspond to the spectrum of carbon, and one of these comet worlds may weigh only a few hundred pounds, and may not contain more solid matter than can be stowed in one's hat. In time to come, when the comet's cosmic dust will have been contracted and condensed, and heat and light will have been evolved, bright lines will mark its progress, and in due time again, as condensation progresses, dark lines such as we now observe in the spectrum of our own sun, in the spectrum of Sirius and that of a host of other stars, will become visible, and in many, many million years, perhaps, when our sun system shall have become old and frigid, and its light and heat shall have been dimmed and exhausted, and life has become extinct in conse- quence thereof, the host of nebulous bodies, now in progress of being born, will assume all the brightness of our present sun, and light up the chaos consequent upon the disappearance of our present sun-system. I have scarcely any time left to point out the use of the spec- troscope in the arts and manufacture. You must be satisfied with one example. You have heard of Bessemer steel. Steel differs from iron in containing less carbon. In the Bessemer pro- cess, carbon and silicon are burned out by oxygen, contained in a blast of atmospheric air, which is thrown through the mass of molten iron. Formerly the manufacture of Bessemer steel was surrounded by great difficulty, for it is necessary to recognize the exact II moment when all carbon is burned out of the iron, or the cast is lost. When this exact moment has arrived, the operation must be stopped instantly; ten seconds more or less will destroy the entire cast. The spectroscope shows this exact moment when the process is finished, and makes the manufacture of Bessemer steel at once an easy and successful task. I think I have touched, like Ithuriel's spear, lightly upon the most salient, technical points necessary, so that you may un- derstand, in how varied a manner, the spectroscope may be utilized. We come now to its application in medicine, and I claim that its usefulness and importance here is second to none I have already mentioned. But to understand how it can show us the effect of anaesthet- ics upon the human system, we must be familiar with the con- stitution of the blood, and learn the optic relations of this vital fluid to the spectroscope, in health and disease. The optic phenomena of blood were not known prior to 1864, when almost simultaneously, Hoppe Seyler, in Tubingen, Ger- many, and Dr. G. G. Stokes, in England, investigated this subject. Stokes pointed out the fact that blood causes a peculiarly strong absorption of light in the yellow and green part of the spectrum. In order to observe this absorp- tion well, the blood should be properly diluted, for in its concen- trated state, the absorption bands between D and E, cannot be observed at all. These two bands are beautifully dark or black, the first which is narrow, more so than the second, which is broader; both are known as the spectral bands of oxidized blood. But blood can exist in a double state of oxidation; that is, it may also exist in a state of complete de-oxidation. The oxidized blood corre- sponds to the arterial; the de-oxidized to the venous blood. When the blood is de-oxidized, the two bands disappear, and are replaced by one dark, broad band, known as Stokes' reduction band. This black band filling the space between D and E, ap- pears whenever the blood is deprived of its oxygen, which it loosely binds. 12 This de-oxidation may be effected by mechanical as well as chemical means. The blood is then called reduced or de-oxi- dized blood. We may deprive blood of its oxygen mechanically by means of an air pump favored by heat. Chemically, blood may be deprived of its oxygen by substances which have an energetic affin- ity for oxygen and absorb it whenever they find it. Tin ammonium, sulphide and others. Blood thus reduced, or de-oxi- dized,may be rapidly re-oxidized by shaking up the solution with atmospheric air. The spectroscope is not idle during these changes; the reduc- tion invariably causes the appearance of Stokes' reduction band; the re-oxidation causes the re-appearance of the two beautiful bands between D and E. The same changes take place in the living economy. In the mean time the discovery was made, that blood con- tained a crystallizable material called haemato-crystalline, also haemo-globulin and cruorine. The great practical importance of this substance must be my apology for entering more minutely into its consideration. Haemato-crystalline is the agent through which oxygen is ab- stracted from the air, and loosely bound in the circulation. Take this crystallizable matter out of the blood and the residue, consisting of albumen, globuline,protagon, cholesterine,sulphur, iron, and some salts, will be quite unable to effect this attraction of oxygen. Haemato-crystalline saturates itself in the lungs with oxygen, it carries its precious burden into the sanguineous circulation, and sustains there the energies of respiration, oxida- tion, and oxygenation. In its course it gives up its oxygen, thus absorbed to all oxidizable tissues with which it comes in contact, and in exchange unites with carbonic acid, which through the venous circulation is brought back to the lungs for elimination, by a process not yet fully understood.—(Hoppe Seyler.) It must be evident to you, that so long as the haemato-crys- talline of the blood remains intact, the same in quantity as in quality, the supply of oxygen to the living economy is subject to relatively unimportant oscillations, and that with the increase i3 or decrease of this substance, or with any change in its integ- rity, rises or falls the vital capacity of an individual's life. That it is beyond any question, the haemato-crystalline, and not any other substance of the blood which enters into and sustains the vital exchanges between the oxygen and carbonic acid, is fully proved by spectral observation. Haemato-cryst. artificially prepared and in solution, is able to absorb oxygen as well as car- bonic acid with great rapidity. It presents two states of oxida- tion, the arterial and venous. It can be oxidized and de-oxi- dized at pleasure; it presents the same absorption bands as blood; it can be reduced, and when shaken up with air, can be readily re-oxidized. It presents the same optical changes when reduced or altered. It enters the same combinations with irre- spirable gases, in short all and every chemical and optical appear- ance which blood presents when acted upon by chemical as well as mechanical agencies, are also observed when these agents act upon a solution of haemato-crystalline. Highly interesting experiments, instituted by Pfluger upon dogs, have given us information of the rapidity with which oxy- gen is used up in the living animal economy. This physicist, forced these animals to inhale nitrogen, which you know does not support respiration. In thirty seconds the highest point of dyspnoea was reached. At this point some blood was abstracted, under the necessary precautions, and then tested for oxygen. It was found that its oxygen was reduced to a minimum, being i to 2 per cent, whilst the blood abstracted from the same animal immediately before it was forced to inhale the nitrogen, contained 18.6 per cent, of the vital gas. As soon as the animals were permitted again to inhale the pure air the dyspnoea disappeared and they seemed as well as ever. You perceive, gentlemen, I have guided you gradually up the hill from which your views will become clearer and fuller. If you will but grasp these facts; presented to you, you will have no difficulty in mastering what follows. Were it possible to observe in the spectroscope the changes taking place in the blood of such a suffocating dog, we would witness a rapid fading away of the two oxygen bands between 14 D and E, and towards the end of the catastrophe one dark band would take their pla :e,the reduced or de-oxidized band of Stokes'; and by the time this band had obtained its full extension and its full depth of shading, poor dog Tray will have gone to his eternal hunting ground. And here comes in the first great lesson in the administration of anaesthetics: "That suffocation will rapidly ensue where anaes- thetics are used, which cannot sustain respiration, or, which is still worse, abstract what supply of oxygen the blood has stored up, unless a sufficient supply of atmospheric air is permitted to be inhaled to sustain life at the same time." The great rapidity with which the dogs, experimented upon, recovered, shows us that the blood itself had not been fatally in- jured or altered. In taking the blood drawn at the height of dys- pnoea, and shaking it up with air, the spectroscope would have promptly informed us of the reappearance of the two oxgyen blood bands, in full depth of shading. To Pfluger's experiments we owe another series of important facts. The amount of oxygen contained in the animal and hu- man blood, 16.9 per cent. Blood-serum contains less than one per cent. The more compact and normal the blood, the more numerous the blood corpuscles are, the greater is the per centage of haemato-crystall.ne, the greater is also its capacity to absorb oxygen ; the poorer the blood, the smaller is its amount. One grain of haemato-crystalline is able to bind 1.27 c. c. of oxy- gen. When we examine spectroscopically the blood of chlorotic per- sons, or that of persons who have sustained severe hemorrhages, or who suffer from pernicious aenemia, bright's disease, fatty de- generation of the heart, or the blood of persons in whom disease has reduced the crystallizable coloring pigment of the blood, as is the case after cholera, typhoid and other diseases, we find the bands paler, and know at once that the normal amount of oxy- gen is wanting in such individuals. Here then comes in our second great lesson. In all cases, due inquiry should be made into the history of the person who is to be placed under the influence of anaesthetics, and if it is found that any of the diseases enumerated above has been present, i5 and that the haemato-crystalline has been reduced by disintegra- tion and retrogressive processes, leaving your patient with pallid countenance and defective heart's action, be on your guard, for what remains, of the vitalized blood, may not be able to resist the effect which your anaesthetic is apt to produce, because in these conditions every anaesthetic agent is dangerous. Let me briefly make you acquainted with agents which per- manently alter the blood. All acids as well as all alkalies are such agents. With these changes we witness corresponding changes in the spectrum, quite definite and characteristic. Here you see on the diagram various spectra resulting; Haematic and Cruentine, Haematcedin, Haenim. I have no time to dwell upon their great importance in spectral analytical investi- gation, but will refer to them by and by. The blood crystals of which we have so often spoken are not found in crystalline form in the blood. They are present there in solution joined to an alkali, probably to potassa carbonate, form- ing haemo-globulate of potassa. (Preyer,) Haemato-crystalline is a weak acid. It can be produced pure, but its preparation is dif- ficult. It crystallizes in rhombic prisms of great beauty and bright red color. AFFINITY FOR IRRESPIRABLE GASES. Wonderful as are the functions of this crystalline material, it possesses qualities whereby destruction to life is invited and facilitated. They have an exceedingly ener- getec affinity for irrespirable and poisonous gases, with some of which they enter into close and inseparable combinations, thereby sacrificing their own integrity and life-supporting power for ever. Some of these irrespirable gases simply dis- ables the haemato-cryst, of the blood to absorb oxygen; others consume all the oxygen of the blood to satisfy their own keen affinity for this gas; others cause a cleavage, or true chemossys, of the haemato-cryst, combining with its alkaline base setting free the crystallizable material, whilst still others cause several of these effects to take place at one and the same time. When a cleavage of the blood material has taken place, the disintegrated elements become foreign bodies and must be elliminated and carried from the system. i6 Preyers experiments upon the dogs, reminds you how rapidly the oxygen is consumed in the animal economy and how neces- sary it is to s-ipply the defect in our equally speedy way; and you can understand how rapidly a fatal result must insue from the action of anaesthetics which, cannot supply the defect, and which in addition greedily appropriate the oxygen which the blood may have stored up and still further destroy the integrity of the haemato-cryst. in a manner so as to paralyse its vital func- tions. Some of these combinations can be obtained in crystal- line form. We can thus produce the prussic acid, the car- bonic oxide, and the nitric oxide haemato-crystalline. The combinations are for stable than the normal oxyhaemato-crystals are. When blood ha.? once entered into a permanent crystalline union with nitrous oxide gas, we know as yet, of no chemical process to restore the resulting nitrous-oxide haemato-crystalline to its normal condition. No electric current posesses the power to restore the primitive integrity of the blood when once brought into this fixed condition. Recently Donders and Young have demonstrated and Podalinsky Julenburg, have corroborated that the haemato-crystalline may be released from the deadly grasp of carbonic oxide by means of carbonic acid, hydrogen and oxygen, being persistently passed through a solution of carbonic oxide haemato-cryst., so that the blood band of jftokes and finally the two bands of oxy-haemato- cryst. may be'reproduced. Whether such a process would suc- ceed, in case of blood saturated with nitrous oxide, whose grasp upon the oxygen of the blood is far more tenacious, is a question which cannot be answered at present. NITROUS OXIDE GAS. Let us begin with this gas, the so called laughing gas, the one so extensively used by surgeons and dentists, and by many con- sidered a serviceable and harmless agent. It has been demonstrated by Herrman and verified by Hoppe Seyler, Gourp Besonez and W. Preyer, that Nitrous oxide gas possesses a very keen affinity for oxidized blood as well as for artificial oxy-haemato-crystalline in solution. The affinity is so 17 strong that when a current of this gas is passed through a solu- tion saturated with carbonic oxide^haemato-crystalline, the car- / _--„ ) bonic oxide is driven out by the nitrous oxide, which takes its ^ place volume for volume. When a current of nitrous oxide gas is forced through a slightly alkline solution of haemato-crystalline, the solution looses its d^chroism and assumes a slight .aarmaiski red color. When f'/T'c**■**' *''**■ the solution is placed before the spectroscope we observe that in proportion that the gas exerts its influence, the two bands be- tween D, and E, fade away and disappear finally altogether, and there is a moment, says Preyer, "when the spectrum is con- tinuous." The disappearance of these blood bands means here, as it means in other instances,d;sappearance of oxygen from the blood, or complete deoxidation, and unless a fresh supply is speedily furnished, suffocation must ensue. As the action of nitrous oxid gas upon the blood solution con- tinues, soon after the fading away of the two bands, two new bands appear, resembling the oxy-blood bands, but differing from them in position and depth of shading; they are paler and more blurred in outlines. Please remember, in this connection, what I said to you about Stokes' reduction band. I then told you that when blood is . . simply deprived of its oxygen, the blood,reduction band would . xo/tas* s* / follow the disappearance of the two oxidized blood bands; and that then, the simple contact of atmospheric air with such de .-- / oxidized blood solution, would suffice to cause the re-appearance of the two oxygen blood bands. But we see here, that instead of Stokes' band, two entirely new bands have made their appearance; and when such blood, satu- rated with the nitrous oxid, is then submitted to the action of reducing agents, the broad band of Stokes, the reduction band, can no longer be produced at all, proving that a more permanent change has taken place in the vital chemistry of the blood. When a current of nitrous oxide gas is passed through a blood solution not made previously alkaline, still further changes take / place. Here a portion of the nitrous oxide gas rapidly oxidizesy #y / at the expense of the oxygen of the blood, and forms hyponitric i8 •£ acid. Preyer holds that this hyponitric/unites _with the haemato- ,/tfrf cryst of the blood in its nascent state. Like all acids, it alters and suspends the coagulability of the blood, and initiates other important chemical and optical changes. This event is marked by the appearance of an absorption in • red to the left of D, from the 53° on Preyer's scale towards D, and another one between b and E. I look upon the appear- ance of this absorption in red as an indication that the union of f-the hyponitric acid has formed and has united with the blood. We already learned that all acids, cyanic acid excepted, cause a decomposition of the blood, and its product is haematine. Now let us logically apply all these ascertained facts to our case in hand, in order to learn how this gas produces its effects upon the economy. ^-^AtT It deprives the blood of its oxygen, and by entering into a ^ ^^£* close combination with its crystallizable material; so bound, it disables this latter to absorb oxygen from the air, or to supply it to the oxidizable tissues of the economy. In Preyer's experiments we have seen that the dogs, when per mitted to inhale oxygen at the highest stage of the disponea, they became rapidly as well as ever. Not so after the inhalation of nitrous oxide gas. A certain effect upon the blood has taken place ; often unim portant and transient; at other times more permanent and grave- sufficient at times, to endanger life itself. We have also seen that under favorable conditions, hyponitric acid is formed, which causes a decomposition of the haemato-crystal- line into haematine a substance which is not capable of sustain- *ng life. Thus we are forced to acknowledge that the application of this gas is far from being safe and harmless ; that on the contrary it is pregnant with grave consequences. " These facts," says a writer in Braithwaite's Reprospect, No. 67, July 1873, "ruthlessly destroy the infatuation, that the inha- lation of nitrous oxide gas is a harmless process, a process which any man, educated or not educated, may carry on without danger of destroying life. The recent death which has occurred at Exter on the afternoon of January 22nd, of this year, furnishes a les- 19 son not to be forgotten. The gas was administered by Dr. F. F. Mason,for the purpose of the painless extraction of a large upper, molar tooth. The lady, Miss Wyndham, was about 38 years of age, in good health. Her physician, Dr. Pattison, was present. Gas from the same source had been administered toother patients so that its quality could not be impugned. She took the gas in the usual way, without any symptoms to excite uneasiness. At the proper degree of insensibility the gas was stopped and the tooth extracted. It was not until after the operation was com- pleted that anything unusual happened; her face suddenly became livid, and the features began to swell, and she seemed to be quite unconscious. She breathed two or three times and in a few moments her pulse ceased to beat. All attempts to restore her were fruitless." "There was no obstruction to the air passages, and the tongue was protruded while she still respired." The writer continues; '"From no agent have there been so many hairbreadth escapes from death as from this gas, and probably of late some persons every day have been brought within the minutest line of danger to which Miss Wyndham succumbed. We learn the most important lesson that we have a great deal to learn before we shall have perfected anaesthetic agents, toward such learning the re-introduction of nitrous oxide gas has been a serious check. "Nitrous oxide gas is indeed not a true anaesthetic at all. A true anaesthetic is an agent that suspends common sensibility^without/* by any necessity, interfering with those organic processes on the continuance of which life depends. Nitrous oxide gas acts by suspending one of the most important of the organic processes, that of respiration. The insensibility produced by this gas, is afforded during an interval of ,partial death. This interval, doubtful, transient, dangerous, may allow an operator time for a short operation, and suspending the inhalation the function may return ; but that it may never return the above case furnishes a lamentable proof." This was written in 1873, and many other cases of death from this gas, are since recorded. Twto years previous to this, in 20 / &«*■ /fj 1871, my warnings had reached England, and had in part been published there in the Medical Times and Gazette, London, January 13th, 1872. It was a lecture delivered before the New York Academy of Medicine, in 1871. Touching nitrous oxide gas I made the following remarks : "No intelligent observer, who ever witnessed the ghastly, cyanosed appearance of persons who have inhaled this gas until its anaesthetic effects are pro- duced, will deny/that the ensemble of symptoms betokens a powerful influence upon the blood mass which continues for many hours and days. I have seen some cases where the inhalation of this gas was followed by pulmonary and cardial disease and death. The profession at large, may yet learn to modify its opinion, regarding ijfe freedom from danger after its application." You may remind me that in a dental institution in New York,^. &*■ we are shown / gigantic rolL containing the names __of jmany__t/ thousands who have inhaleu this gas there, so far, without any direct fatal effect. But how is it with after effects? The institution, referred to A —-- keep! no record of what becomes of its patients afterwards. One^ of my fatal cases — dying from after effects—had inhaled the gas xh#*e three or four months previous. She was a perfect- ly healthy woman before the inhalation, and her disease began right after it. Other well authenticated cases are not wanting to prove, that nervous disorders, of many kinds, and a train of organic diseases, follow^ its exhibition. ADr. F^R. Thomas, in Tiis treatise on~TZNitrousOxide gas," says: "It resembles strong- ly in its effect an attack of Congestive Apoplexy. Many are de- prived of sleep long afterwards, and complain of unremitting headaches; nor are instances rare, where, after its use, vertigo, syncope, melancholy, insomnia, convulsions, hesteria, and irreg- ular heart's action, could be attributed directly to its use." (Dr. Geo. J, Ziegler's researches on nitrous oxide.) Having fully pointed out to you the manner in which nitrous oxide gas effects the blood, it must serve you as a type for all those agents which deprive the blood of its oxygen, and form stable crystalline compounds with the haemato-crystalline of trre/^\ .blood, whereby &t&r life function is gravely impaired, and under ^ certain conditions forever lost. { '> \«J /"V^1 \vv \ \ \ \ In case of accident with nitrous oxide, our indications are con- fined to narrow limits. We must try to economise the still in- tact blood corpuscles, and by transfusion, and especially by ar- tificial respiration, ^ favor a full and long supply of oxygen to , sustain the little flame of light. Electricity may be used to keep up the muscular action of the heart and lungs. We may thus succeed to organize the accumulated nitrous oxide, and to elim- h .-t , a inate it from the system. P-odowaky has thiiSrGuccccdcd in some'^* /£$>***' ^> almost hopeless cases of poisoning with carbonic oxide, and the—~^_. yi^^^/\) proceedure seems to me well adapted also in cases of poisoning /fA^