CHEMICAL NEWB, The Molecular Dissymmetry of Natural Organic Products. April 26, 1862. It is well known that sulphurous acid gis prevents alcoholic and acetic fermentation, as well as the fermentation of animal matters and of organic matters in general. Thus it arrests, if it be already begun, the fermentation produced by saliva and diastase in contact with starch, the fermentation occasioned by myrosine in a paste of black mustard-flour, that produced by emulsine on the amygdaline of bitter almonds, &c. M. Polli has proved that alkaline or earthy sulphites possess the same antiseptic and decolorising properties. This is an important fact, since it allows of the application of sulphurous acid in therapeutics. He thinks that he has grounds for believing that the action of sulphurous acid and sulphites on colouring matters, as well as on ferments, is not a deoxygenation, nor a combination, nor destruction, but simply a molecular modification. This action of sulphurous acid and sulphites affords an explanation of the valuable property possessed by these chemical compounds of preventing, or energetically arresting, the action of morbific ferments artificially introduced into the blood of animals, without altering its composition in a manner incompatible with life. From a number of experiments on dogs, mentioned in his memoirs, M. Polli has determined the quantity of the safe and efficacious dose of sulphite for internal administration, the changes they undergo in the organism, and their curative action on affections produced by injecting putrid or contagious matters into the blood. The following are some of his experiments, selected from those of the last-mentioned series:: 1. Ten grammes of sulphite of soda were given to a dog in a space of five days, then one gramme of pus was introduced into the femoral vein. The animal became spiritless and refused food, but its spirits returned the next day, and it ate willingly. The experiment repeated two days after, yielded a like result. The animal was perfectly cured in a few days. 2. One gramme of pus was injected, in two portions, into the veins of a dog more robust than the subject of the preceding experiment. The amimal became dull, but ate the next day; the following day it was very low, the breathing difficult, the wounds sanious, the left leg and foot swelled, and it died ten days after. 3. An equal quantity of putrid blood was introduced into the veins of three dogs; one died five hours after, another after five days' illness, and the third, to which some sulphite of soda had been given, recovered rapidly after a little illness. 4. Numerous other experiments with putrid blood and glandered mucus prove that animals die with every symptom of general infection, whenever sulphite of soda is not administered, and that, on the contrary, they speedily recover under the influence of this medicament. If these facts are confirmed by other experiments, M. Polli will have rendered an inestimable service to therapeutics, and will have thrown some light on the still obscure origin of numerous diseases. PHYSICAL SCIENCE. On the Molecular Dissymmetry of Natural Organic Products, by L. PASTEUR, Member of the Chemical Society of Paris. (Continued from p. 204.) III. HERE we encounter a fact worthy of fixing the attention, even though we should regard it alone and 231 isolated from the whole of the considerations about to follow. It is this: All artificial products of the laboratory, and all mineral species, have a superposable image, On the contrary, most of the natural organic products (I might say all, if I had to name only those which play an essential part in the phenomena of animal and vegetable life), all products essential to life are dissymmetric, and of the dissymmetry which causes their image to be non-superposable. Before proceeding further, I desire to set aside some objections which cannot fail to present themselves to your minds. IV. Quartz, you will say, is one. We have seen in the last lecture that quartz possesses the two characters of dissymmetry,-the hemihedrity in form observed by Haüy, and the rotary phenomena discovered by Arago. Nevertheless, all molecular dissymmetry is absent in quartz. To understand it, let us advance a little further in the knowledge of the phenomena we are considering. We shall find, moreover, the explanation of the analogies and differences already previously indicated between quartz and natural organic products. Permit me to describe roughly, though in the main accurately, the structure of quartz and that of natural organic products. Imagine a winding stair, the steps of which shall be cubes, or any other object with a superposable image. Destroy the stair, and the dissymmetry will have disappeared. The dissymmetry of the stair was the result only of the mode of putting together its elementary steps. Such is quartz. The crystal of quartz is the stair all built. It is hemihedric. For this reason it acts on polarised light. But let the crystal be dissolved, melted, -its physical structure destroyed in any manner, and its dissymmetry is suppressed, and with it all action on polarised light, as would happen, for example, in a solution of alum, a liquid formed of molecules of a cubic structure distributed without order. Imagine, on the contrary, the same winding stair formed of irregular tetrahedrons for steps. Destroy the stair, and the dissymmetry will still exist, because you have to deal with an assemblage of tetrahedrons. They may be in any position, but each one of them will have its proper dissymmetry, nevertheless. Such are organic bodies in which all the molecules have a proper dissymmetry, which is translated in the form of the crystal. When the crystal is destroyed by solution, there results from it a liquid active for polarised light, because it is formed of molecules pell-mell, it is true, but each having a dissymmetry in the same direction, if not of the same intensity in all directions. V. Quartz, then, is not molecularly dissymmetric, and, up to the present time, we do not know any example of a mineral which possesses molecular dissymmetry. I have said that we must extend this proposition to the artificial compounds of laboratories. Here still we may have some scruples. We may object, for example, that native camphor, which is dissymmetric, yields artificially camphoric acid, also dissymmetric; that aspartic acid is derived from asparagine,—and I might cite many other like examples. But no one doubts that camphoric and aspartic acids owe to camphor and to asparagine their and it is transferred, modified more or less by substitu proper dissymmetry. This exists in the mother products, tion, from the mother products to their derivatives. We are unable to produce better evidence in general, of the preservation of the primitive type in a series of products connected by a common origin, than the permanence of the optic property. When I affirm that no artificial substance has yet presented molecular dissymmetry, I mean to speak of artificial substances, properly so called, formed entirely of mineral elements, or derived from non-dissymmetric bodies. For example, alcohol is not dissymmetric. Its moleculi, if we could isolate and study it, placed before a mirror would present an image superposable to it. Now, there is no derivative from alcohol which is not dissymmetric. I could multiply examples of this kind without end. Further, take any dissymmetric body, and if you subject it to somewhat energetic chemical reactions, you will assuredly see the dissymmetry of the primitive group disappear. Thus, tartaric acid is dissymmetric. Pyrotartaric acid is no longer so. Malic acid is dissymmetric. Maleic and paramaleic acids of M. Pelouze are not. Gun is dissymmetric, mucic acid is not. Artificial products, then, have no molecular dissymmetry. I do not know how to indicate the existence of a more perfect separation between the products originating under the influer.ce of life and all others. We insist a little, because you will see in the sequel of this lecture the physiological aspect of these studies disengages itself more and more. Let us pass in review the principal classes of natural organic products. Cellulose, feculæ, gums, sugars, tartaric, malic, quinic, tannic acids, morphia, codeia, quinia, strychnia, brucia, essence of turpentin, of lemon, albumen, fibrin, gelatin. All these immediate principles are molecularly dissymmetric. All these substances have the rotary power when in solution; a character necessary and sufficient to establish their dissymmetry, even when, in the absence of possible crystallisation, hemihedrity would be wanting for the recognition of this property. All the substances most essential to the vegetable and animal organism figure in this enumeration. There are many natural substances which are not dissymmetric. But are they natural in the same sense as the others? Do we not necessarily see in such bodies as oxalic acid, hydruret of salicyle, fumaric acid, the derivatives of natural substances properly so called, formed by actions analogous to those of the laboratory? These products seem to me to be in the vegetable organism what urea, uric acid, creatine, glycocol, are in the animal organism, rather excretions than secretions, if I may so speak. It will be very interesting to follow this point of view experimentally. We may add to this, that many bodies, non-dissymmetric in appearance, may be paratartarics. A word is wanting in chemical language to express the fact of a double molecular dissymmetry concealed by the neutralisation of two inverse dissymmetrics, the physical and geometric effects of which rigorously compensate each other. The double proposition to which we have just been led upon the habitual dissymmetry of immediate organic principles, and upon the absence of this character in all the products of inorganic nature, enables us to enlarge and render more and more precise our manner of viewing the subject of this remarkable molecular property. VI. In 1850, M. Dessaignes, whose ingenious skill is known to chemists, announced to the Academy that he had succeeded in transforming the bimalate of ammonia into aspartic acid. It was a step which tended to confirm the important results that M. Piria had obtained some years previously. M. Piria had succeeded in transforming asparagine and aspartic acid into malic acid. M. Dessaignes in his turn showed inversely that malic acid could be reformed into aspartic acid. Thus far there was nothing but what was very natural in the observation of M. Dessaignes, even in the optical point of view. For my part, I had recognized that asparagine, aspartic acid, and malic acid, were active on polarised light. The chemical passage of one of these bodies to the others was not surprising. Some months later, M. Dessaignes made another step forward. He announced that not only the binalate of ammonia, but also the fumarate and maleate of ammonia had equally the property of being transformed by heat into aspartic acid. Here I perceived an impossibility; or, if the thing was as M. Dessaignes asserted, this skilful chemist had made a discovery which he did not suspect. Indeed, I observed that fumaric and malic acids and all their salts were without action on polarised light. If, then, M Dessaignes had succeeded in transforming their salts of ammonia into aspartic acid, he must have realised for the first time the production of a dissymmetric body by the aid of compounds which are not. But it appeared to me more reasonable to believe that the aspartic acid of M. Dessaigues differed from natural aspartic acid decidedly in the absence of the molecular rotary property. M. Dessaignes, it is true, had carefully compared the properties of the artificial acid with those of the natural acid, and, as he said, found them identical. Better than any one, from the example of M. Mitscherlich, of whom I spoke at our last meeting, I knew how delicate is the determination of the identity of chemical species in studies in which the greatest similitude of properties often conceal profound differences. I did not hesitate to believe, therefore, that the new fact announced by M. Dessaignes had need of confirmation. I attached so much importance to the clucidation of this question, and in the anticipation even of the results which I am about to have the honour to lay before you, that I immediately made a journey to Vendome, where I submitted my doubts to M. Dessaignes, who at once presented me with a specimen of his aspartic acid. On my return to Paris, I found immediately, in fact, that the acid of M. Dessaignes was only an isomer of the natural aspartic acid, that is, the acid derived from asparagine, and that it differed from it, as I had foreseen, by the rotary property, entirely absent in the artificial acid, not at all doubtful in the natural acid. But all the other physical and chemical properties possessed the greatest analogies, so great that M. Dessaignes, who was not put on his guard by any preconceived idea, had concluded that the two substances are really identical. What attracted me most in the examination of the new compound (which by itself offers no very remarkable crystallisable combinations), was its transformation into malic acid. It is, indeed, known that M. Piria, just mentioned, long ago gave the means of obtaining malic acid from asparagine and aspartic acid, and I was assured by the most exact proofs that this malic acid was identical with that of the sorbus, the apple, the grape, and tobacco. I then treated the new acid in the manner discovered by M. Piria, and transformed it into a new malic acid very similar to the natural acid, so close to the latter, that a chemist would have great difficulty in distinguishing them even if warned of their real dissimilarity; only this malic acid had no action on polarised light, and it was the same with all its saline combinations. There are certain derivations of these two malic acids, the comparison of which does not very clearly manifest the true mutual dependence of the molecular arrange April 26, 1862. Effect of Temperature upon Light Emitted by Certain Metals. 233 ments of these curious isomerics; but there are others in the vapour of this metal is intensely heated, and the which it is plainly seen. Let us consider, for example, common blue strontium line called Sr. 8. We further the ordinary active bimalate of lime, and the correspond-stated that on investigating the subject more narrowly ing inactive bimalate. Their chemical composition is exactly the same, and their crystalline forms are alike, with this difference, that the form of the active bears four small hemihedric faces, always absent in the form of the inactive. Whence it results that placed before a glass the image of the active cannot be superposed on it, while the image of the inactive is absolutely identical and superposable to the reality which gives it. Excepting the hemihedric faces, there is a perfect resemblance between the two forms. Who could doubt, after that, the relations of molecular arrangements of these two salts ? Is it not evident that we have here to deal with a malic acid identical to the natural, except the simple suppression of its molecular dissymmetry? This is the natural malic acid untwisted, if I may so express it. The natural acid, in the arrangement of its atoms, is a winding stair; this one is the same stair, formed of the same steps, but straight, instead of being spiral. It might now be asked if the new malic acid is not the paratartaric of the series; that is, the combination of the right malic acid with the left malic acid. That is scarcely probable; for then, not only with an inactive body we would have made an active body, but would have made two, one right and one left. Besides, I have ascertained that just as there exists a non-dissymmetric inactive malic acid, so there is also a non-dissymmetric inactive tartaric acid, very different from paratartaric acid, and which cannot be resolved into right tartaric and into left tartaric acids. Here it cannot be doubted that we have to deal with right or left tartaric acid rendered non-dissymmetric. I have also discovered inactive amylic alcohol, which yields a whole series of inactive products corresponding to the series of active amylic alcohol. Thanks to the discovery of inactive bodies, we are in possession of a fruitful idea: a substance is dissymmetric. right or left, by certain modes of isomeric transformations, which must be sought and discovered in each particular case; it may lose its molecular dissymmetry, untwist itself, to use a coarse illustration, and effect in the arrangement of its atoms a disposition with a superposable image. So that every dissymmetric substance offers four varieties, or, rather, four distinct sub-species: the right body, the left body, the combination of the right and the left, and the body which is neither right nor left, nor formed by the combination of the right and left. (To be continued.) On the Effect of Increased Temperature upon the Nature of the Light Emitted by the Vapour of certain Metals or Metallic Compounds, by Professors Roscoe and CLIFTON. In a letter communicated to the Philosophical Magazine for January last, we stated that in examining, with Steinheil's form of Kirchhoff and Bunsen's apparatus, the spectra produced by passing the induction spark over beads of the chlorides and carbonates of lithium and strontium, we had observed an apparent coincidence between the blue lithium line, which is seen only when Read at the the last meeting of the Manchester Literary and Philosophical Society. by the application of several prisms and a magnifying power of 40, we came to the conclusion that the lithium blue line was somewhat more refrangible than the strontium 8, but that two other more refrangible lines were observed to be coir.cident in both spectra. Having constructed a much more perfect instrument than we at that time possessed, we are now able to express a definite opinion on the subject, and beg to lay a short notice of our observations before the Society. Our instrument is in all essential respects similar to the magnificent apparatus employed by Kirchhoff in his recent investigations on the solar spectrum and the spectra of the chemical elements. It consists of a horizontal plane cast iron plate, upon which three of Steinheil's Munich prisms, each having a refracting angle of 60°, are placed; and of two tubes fixed into the plate, one being a telescope having a magnifying power of 40, movable with a slowmotion screw about a vertical axis placed in the centre of the plate, and the other being a tube carrying at one end the slit, furnished with micrometer screw, through which the beam of light passed, and at the other end an object-glass for the purpose of rendering the rays parallel. The luminous vapours of the metals under examination were obtained by placing a bead of the chloride or other salt of the metal on a platinum wire, between two platinum electrodes, from which the spark of a powerful induction coil could be passed. In order to obtain a more intense, and therefore a hotter, spark than can be got from the coil alone, the coatings of a Leyden jar were placed in connection with electrodes of the secondary current respectively. When this arrangement was carefully adjusted, the two yellow sodium lines were observed to be separated by an apparent interval of two millimètres, as seen in the least distance of distinct vision. The position of the blue line, or, rather, blue band of lithium, was then determined with reference to the fixed reflecting scale of Steinheil's instrument, by volatilising the carbonate of lithium, in the first place on a platinum wire between platinum electrodes, and secondly, on a copper wire between copper electrodes. A bead of pure chloride of strontium was then placed on new platinum and copper wires between two new platinum and copper electrodes, and the position of the blue line Sr. & read off upon the same fixed scale; a difference of one division on the scale was seen to exist between the positions of the two lines, the lithium line being the more refrangible. The salts of the two metals were then placed between the poles at the same time, and both the blue lines were simultaneously seen, separated by a space about equal to that separating the two sodium lines. When experimenting with this complete instrument, we were unable to observe any other blue lines in the pure lithium spectrum than the one above referred to; we have, however, noticed the formation of four new violet lines in the intense strontium spectrum, and we now believe that the other two lithium lines mentioned in our letter to the the most minute traces of strontium floating in the atmo Philosophical Magazine are caused by the presence of sphere, and derived from a previous experiment. We the currents of air caused by the rapid passage of the have convinced ourselves by numerous observations that electric spark between the electrodes are sufficient to carry over to a second set of electrodes placed at the distance of a few inches, a very perceptible quantity of the materials undergoing volatilisation. The great NOWE precautions must hence be taken when the spectra of two metals have to be compared; and no separate observations of the two spectra can be relied upon, unless one is made a considerable space of time after the other, and unless all the electrodes which have been once used are exchanged for new ones. Kirchhoff, in his interesting "Memoir on the Solar Spectrum and the Spectra of the Chemical Elements,"+ noticed in the case of the calcium spectrum that bright lines which were invisible at the temperature of the coalgas flame became visible when the temperature of the incandescent vapour reached that of the intense electric spark. We have confirmed this observation of Kirchhoff's, and have extended it, inasmuch as we, in the first place, have noticed that a similar change occurs in the spectra of strontium and barium; and, in the second place, that not only new lines appear at the high temperature of the intense spark, but that the broad bands characteristic of the metal or metallic compound at the low temperature of the flame or weak spark, totally disappear at the higher temperature. The new bright lines which supply the part of the broad bands are generally not coincident with any part of the band, sometimes being less and sometimes more refrangible. Thus the broad band in the flame-spectrum of calcium named Ca B, is replaced in the spectrum of the intense calcium-spark by five fine green lines, all of which are less refrangible than any part of the band Ca B; whilst in place of the red or orange band Ca a, three more refrangible red or orange lines are seen. The total disappearance in the spark of a welldefined yellow band seen in the calcium spectrum at the lower temperature, was strikingly evident. We have assured ourselves by repeated observations that, in like manner, the broad bands produced in the flame-spectra of strontium and barium compounds, especially Sr a, Sr ß, Sry, Ba a Ba 8, Bay, Ba 8, Ba e, Ban, disappear entirely in the spectra of the intense spark, and that new bright non-coincident lines appear. The blue Sr & line does not alter either in intensity or in position with the alterations of temperature thus effected, but, as has already been stated, four new violet lines appear in the spectrum of strontium at the higher temperature. If in the present incomplete condition of this most interesting branch of inquiry we may be allowed to express an opinion as to the possible cause of the phenomenon of the disappearance of the broad bands and the production of the bright lines, we would suggest that at the lower temperature of the flame or weak spark, the spectrum observed is produced by the glowing vapour of some compound, probably the oxide, of the difficultly reducible metal; whereas, at the enormously high temperature of the intense electric spark, these compounds are split up, and thus the true spectrum of the metal is obtained. In conclusion, we may add that in none of the spectra of the more easily reducible alkaline metals (potassium, sodium, lithium) can any deviation or disappearance of the maxima of light be noticed on change of temperature. On a Means of Increasing the Intensity of Metallic I HAVE for some years been in the habit of employing "Kirchhoff on the Solar Spectrum," &c. Translated by H. E Roscoe. Macmillan, Cambridge. 1862. cult to imagine anything more gorgeous than some of the spectra thus produced. A small lump of chlorate of baryta, supported within the sixteenth of an inch of a colourless gas flame, decomposes with decrepitation, imparting its peculiar green and red tints to the flame, and exhibiting in the spectroscope an appearance perhaps unsurpassed in the whole range of metallic spectra. Each line stands out with extreme brilliancy, and a multitude of new lines, both green and red, come into view. A fused bead of chlorate of potash being introduced into the flame, decomposes at first with less rapidity than the baryta salt, but after a few moments it goes off with almost explosive violence, whilst at the same time that portion of its spectrum which is usually continuous splits up in parts into numerous fine lines. Chlorate of soda sometimes gives an appearance of inversion, the usual line appearing dark on a dazzlingly brilliant ground. On shading off the more luminous portion of its spectrum, traces of lines were visible in the more refrangible portion. Chlorate of lithia gives, in addition to the red and orange line, the very brilliant blue line observed in its electric spectrum. Another more refrangible blue line is also seen when the ignition is at its greatest intensity. Chlorate of strontia shows, in addition to brilliant lines in the lower portion of its spectrum and the well-known blue line, three other blue or violet lines some distance apart. Chlorate of lime gives the blue band very brilliantly, and several other lines hitherto unrecorded. Besides these, many other metals show brilliant and characteristic spectra when ignited in the form of chlorates. Copper is especially vivid, and its spectrum is remarkable for changing its appearance according to the state of decomposition of the chlorate, the final spectrum differing in several respects from the one observed when the salt is first introduced into the flame. The lead and cadmium spectra are also very beautiful, and exceedingly definite. ment of the chlorates gives us a ready means of proIt will be seen from the above notes that the employducing spectra of an intensity which approaches that high degree hitherto only obtainable by the employment lines mentioned by Professors Roscoe and Clifton being of the electric spark; the blue strontium and lithium readily visible by this means. The chlorates may be readily prepared by precipitating chlorate of baryta (which may be obtained in commerce) by the desired sulphate or carbonate, and evaporating the filtrate; or by adding to it the equivalent quantity of sulphuric acid, filtering through asbestos or guncotton, and neutralising the resulting chloric acid with the metallic carbonate or oxide. Unfortunately, I have not succeeded in obtaining any characteristic spectrum from arsenic in any of its compounds. A delicate spectrum test for this metal would be of the highest importance to toxicologists, but it appears, with the means I have employed to examine it, to give a continuous spectrum. Antimony, likewise, gives no better results. Royal Institution. — Tuesday, April 29, at Four o'clock, C. T. Newton, Esq., "On Ancient Art." Thursday, May 1, at Two o'clock, Annual Meeting. Friday, May 2, at Eight o'clock, R. M. Milnes, Esq., M.P., " On the International Exhibition." Saturday, May 3, at Thre o'clock, Professor Anderson, "On Agricultural Chemistry." CHEMICAL NEWS, } April 26, 1862. Chemical Society-Notices of Books. PROCEEDINGS OF SOCIETIES. CHEMICAL SOCIETY. Thursday, April 17, 1862. Dr. A. W. HOFMANN, F.R.S., President, in the Chair. A PAPER, by Dr. E. DIVERS," On the Action of Bicarbonate of Ammonia upon the Salts of Magnesia," was read by the Secretary. It had usually been supposed that magnesia was only partially precipitated from solution by carbonate of ammonia, and not at all in the presence of a sufficient quantity of ammoniacal salt; this, however, was not strictly correct, for on adding a solution of carbonate of ammonia to a solution of sulphate of magnesia a precipitate was produced, and this took place even in the presence of a large quantity of chloride of ammonium. If an excess of carbonate of ainmonia were added, the pre: cipitate consisted of a double carbonate of magnesia and ammonia; to produce this double compound, at least four equivalents of carbonate of ammonia for every equivalent of magnesia were necessary. In a very dilute solution no precipitate was produced, unless a considerable excess of carbonate of ammonia were added; but after this addition a precipitate was produced, when the solution contained only oth part of magnesia. The precipitated double carbonate contained single equivalents of magnesia and ammonia. The solubility of the precipitate in water and ammoniacal salts was then tried. On washing a portion of the salt on a filter with water, part was dissolved, while the remainder was decomposed into carbonate of ammonia, which dissolved, and carbonate of magnesia, which remained on the filter. On projecting the salt gradually into a large quantity of water, it dissolved to some extent, but as soon as the water was saturated it began to decompose the excess of salt. A solution prepared in this manner might be kept for some time without decomposing; but the addition of carbonate of ammonia produced a precipitate. A solution of chloride of ammonium dissolved a smaller quantity of the salt than pure water; and it was almost insoluble in water containing carbonate of ammonia. It was desirable to have a process for preparing this double salt with facility, as it promised to be useful in medicine. The PRESIDENT said that it was curious that the insolubility of carbonate of magnesia in ammoniacal salts should have been overlooked for so long a time, but the probable reason was that the precipitation only took place after some time. Professor GRAHAM remarked that it was not mentioned in the Paper which had just been read, what carbonate of ammonia was used, but that it was probably the sesquicarbonate; he considered that carbonic acid might be viewed as a tribasic acid, for a compound might be prepared containing the three bases-potash, magnesia, and water-combined with three equivalents of carbonic acid; sesquicarbonate of soda was also an analogous compound. The PRESIDENT remarked that the bibasic character of carbonic acid was borne out by the manner in which it was set free during the action of reagents on organic compounds; under these circumstances two equivalents of carbonic acid were almost always evolved; also, that with respect to the precipitation of magnesia, the solution was generally rendered very alkaline with ammonia before precipitation, under which condition the carbonate would not perhaps form so readily; he also stated that Mr. Watts had written a note on the Paper to the effect that this precipitation of magnesia by carbonate of ammonia was referred to in Rose's "Handbook of Analysis." The PRESIDENT then made a verbal communication on some organic compounds obtained from the refuse of the manufacture of aniline. The products obtained at different aniline works varied to a considerable extent in 235 Towards the end of the their nature; and this variation appeared to be due to a difference in the hydrocarbons employed in the manufacture; for in England, that portion of the coal oil which boiled below 100°C. was employed, but at some works in France, all that distilled below 120°C. was considered fit for the purpose; in fact, there existed in coal-tar a substance (which had been examined by Mr. Church) having the same composition and vapour density and especially in its boiling point, which was 98°C., so as benzol, but differing from it in some of its properties, that only a small portion of this would distil below 100°C., the greater part being held back by the hydrocarbons distillate by the method for preparing aniline, a great possessing a higher boiling point. On treating this number of substances were obtained; these had not as yet been completely examined; they might be separated distillation two fatty bodies passed over, which were so by fractional distillation. viscid that the vessel containing them might be inverted; but they did not crystallise. They both, however, formed crystallised salts with acids, and the sulphate of one of the bases was almost insoluble in water, the other sulphate being soluble; by this means the two bases might be separated; the salts of that forming the more soluble uranium in colour; it was isomeric with aniline, but sulphate were fluorescent, and resembled those of combined with only half as much acid, so that the formula chlorate being 12 H1, N2, HCl. The composition of the would have to be doubled, the composition of the hydroother base was expressed by the formula 12 H11 N, the hydrochlorate containing C, H, N, HC1; this agreed in composition with diphenylamine, a substance which could not be prepared by a process similar to that employed for the formation of the corresponding ethyl compounds, since the chloride of phenyl had no action on ammonia. NOTICES OF BOOKS. On Pepsine. By M. BOUDAULT. Translated by W. S. Squire, Ph.D., F.C.S. Second Edition. Churchill, London. THIS is the translation of a paper read by M. Boudault before the Paris Academy of Medicine. The Parisian Scientific Societies resemble in one respect our Society of Arts, and also some of our Medical Societies. Any person with an invention to make public, reads a paper before these Societies, investing the subject with a certain amount of scientific interest to save appearances, and then the communication is forthwith published, the implied autho. rity of the Society being found to be a first-rate advertisement. M. Boudault's paper is a very good account of the properties of natural pepsine, or rather gastric juice, concluding with a recommendatory notice of Pepsines, Nos. 1, 2, 3, and 4, prepared by the author. An account of the manner in which pepsine is said to be made will be found at page 54, vol. ii., of the CHEMICAL NEws, in an interesting paper by Mr. Napier, of Dublin, to which we refer any of our readers to whom the subject may be a novelty, with the additional information that pepsine is now principally obtained from the stomachs of pigs, and an enterprising man would no doubt do well if he set up a laboratory at Cork or Waterford. The anatomists of the School of Salerno, in the absence of human "subjects," dissected the bodies of swine, "as likest the human form divine"; and according to some chemists, the gastric juice of the same quadrupeds bears the nearest resemblance to that of man. The value of pepsine (manufactured pepsine we mean) as a medicine is differently estimated by medical men. Dr. Chambers, in a lecture appended by Dr. Squire to M. Boudault's paper, praises it highly; while Dr. Leared, in |
