Imatges de pàgina
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his work on "Imperfect Digestion," altogether denies its value. We cannot undertake to arbitrate in the matter, but infer that pepsine sometimes does good and sometimes does not. Dr. Squire has done well to bring M. Uoudault's paper under the notice of tbe profession, and medical men will judge for themselves. What natural pepsine is they will learn distinctly enough from this paper. What commercial pepsine is and has been, is a different question, on which if we had time and space a good deal might be said.

NOTICES OP PATENTS.

Dated

1364. Paper. E. Hartnall, Ryde, Isle of Wight

May 31, 1861. (Not proceeded with.) It is proposed to employ in the manufacture of paper a certain kind of sea-weed called zosttra marina, which is very abundant on our shores and occurs in the form of pale green, rounded concretions. This vegetable production is known also under a great variety of designations, such as "grass-wrack," "oar-weed," sea-apples," &c. j and under the French synonym of "Pommel de mer," a patent was granted for the same application to M. #Mennons,» on May 3, 1861, who appears thus to have anticipated Mr. Hartnall's invention.

1367. Alkaline Carbonates. R. Laming, Priory Road, Kilburn. A communication. Dated May 31, 1861. (Not proceeded with.) The inventor employs the sulphate of soda or potash as the starting-point from which to manufacture the carbonates of these bases. He mixes the sulphate with any suitable carbonaceous matter, and prepares a crude alkaline sulphide by exposing this mixture to a high temperature in a crucible or convenient furnace. The product obtained in this manner is charged into a long tube and steam mixed with air passed over it as long as sulphuretted hydrogen continues to be evolved, when tbe residual product is removed and treated with water to dissolve out the carbonate of soda or pota6h, which may then be purified by crystallisation or in any other way.

1382. Obtaining Products from Coal. W. A. Suepabd,

Fall Mall, London. Dated June 1, 1861. For the purposes of this invention, comparatively large blocks of coal are introduced into closed chambers of firebrick, iron, or other suitable material, where they are submitted to a process of slow distillation. Atthe lowarpart of this chamber is a smell fire-place, which is separated from the main receptacle for the coal by a set of vertical bars or grating, thus furnishing a means of starting the process of distillation from without. From the back of the chamber, at different levels, are two outlets, which lead the products into separate condensing arrangements, the highly volatile matters, selecting by preference the upper exit pipe, and in order to facilitate the escape of th?se vapours a jet of steam is employed to establish a current in the required direction. At the lower outlet the tarry products and heavy oils are principally collected, these run off into a tank provided for their reception. The coal from which products are to be obtained is placed in an iron crate or bosket, which corresponds in dimensions with the interior of the chamber, and the construction is so arranged that it may be lowered from above into the chamber, the upper port of which is then closed to prevent the escape of any products from the coal; or the nont grate being movable the crate holding the charge may be run in or trucks. A fire having been kindled in front of the vertical grating, the flames pass through and ignite the lower portion of the charge, the coals in the chamber thus become coked gradually, and further from

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the fire as the process is continued, whilst the products are collected in the manner described.

An arrangement very similar to the above was that originally used for the purpose of obtaining paraffin and other matters from Irish peat. It was, however, more simple in construction, and provided with only one outlet for the escape of the volatile products.

Granti of Provisional Protection for Six Month*.

264. Edward Henry Cradock Monckton, Fineshade, Northamptonshire, "Improvements in the application of electricity for obtaining ammonia and other useful products duiing the combustion of coal and fuel, and in the apparatus employed therein."—Petition recorded 31st January, 1862.

614. Richard Wright, Albany Road, Camber-well, Surrey, "Improvements in heating and clarifying saccharine fluids."

638. James Duncan, Greenock, Renfrewshire, N.B., "Improvements in the manufacture of vinegar."

704. George Bennet, Manchester Building!), Westminster, Middle-ex, " An improvement in the coating and covering of wrought iron for the purpose of preserving it and preventing oxidation."

715. George Brooks Pettit, New Oxford Street, London, "An improved method of and apparatus for heating water and other liquids, applicable also to the evaporation of liquids."

747. Marc Antoine Francois Mennons, Rue de l'Echiquier, Paris, "The application to the manufacture of paper pulps of a vegetable product not hitherto used for that purpose."—A communication from Frederic Thierry PitoyMillot, Faubourg St. Pierre, Nancy, Departemeut de la Meurthe, France.

750. Henry Bailly, Salter's Hall Court, Cannon Street, London, "Improvements in the manufacture of paper from wood, and in apparatus used therein."—A communication from Ernest Antreux and Michel and Joseph Cotton, La Rochelle, Lower Charente, France.

822. Alfred Fryer, Manchester, "Improvements in the manufacture of sugar, and in separating liquids from sugar and other substances."

830. Leo de la I'eyrouse, Panton Square, Middlesex, "Improvements in the preservation of animal substances."

Notices to Proceed.

2861. Henry Bird, Liverpool, "Improvements in the construction of bottles and other vessels, and in stoppers for the same to indicate whether they contain poison."— Petitions recorded 13th November, 1861.

2903. Theophilus Redwood, Montague Street, Russell Square, London, "Improvements in the manufacture of starch, and of a vegetable sizing powder."—Petitions recorded 19th November, 1861.

2972. Charles Stevens, Charing Cross, London, "An improved indelible anti-corrosive ink."—A communication from Louis Croc, Paris.

3108. William Heniy Tooth, Rhodeswell Road, and William Yates, jun., Parliement Street, Westminster, London, "Improvements in the manufacture of iron and steel, and in the machinery, apparatus, or furnaces used therein, and for the production of gas to be employed in such manufacture."—Petition recorded nth December, 1861.

264. Edward Henry Cradock Monckton, Fineshade, Northamptonshire, "Improvements in the application of electricity for obtaining ammonia and other useful pro"ducts during the combustion of coal and fuel, and in the apparatus employed therein."—Petition recorded 31st January, 1862.

583. Henry Bunning, Field House, New Cross, Deptford, Kent, "Improvements in the manufacture of lubricating grease or compounds."—Petition recorded 3rd March, 1862.

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289. Thomas Mossom Meek ins, LL.D., Chancery Lane, London, '* The production of a projectile and explosive force to be used in instruments of war, for an electric gas gun and electric gas shell, for a method of using the recoil of weapons for the purpose of increasing the pressure of elastic fluids for the production of a projectile force, for a method of rapidly loading weapons at the breech, and of a motive .force to be used in an electric gas engine or other engines."—Petition recorded 4th February, 1862.

340. James Dickson, Tollington Road, Holloway, Middlesex, " Improvements in voltaic apparatus, and in the production of voltaic electricity."—Petition recorded 10th February, 1862.

700. John Kent, Hyson Green,Nottingham, "Improvements in cleansing and bleaching."—Partly a communication from Theodor Schnebely, Moscow.—Petitions recorded 13th March, 1862.

720. Henry Young Darracott Scott, Brompton Barracks, near Chatham, Kent, "Improvements in the manufacture of cement."

3002. Peter Spence, Newton Heath, Manchester, "Improvements in the treatment of ores for the manufacture of sulphuric acid, and in apparatus connected therewith." —Petition recorded 28th November, 1861.

3030. James Leach, Bronte Place, East Street, Walworth, Surrey, "Improvements in preparing matters to be used in the manufacture of candles."

COBBESPONDENCE.

Utilisation of Sewage.
To the Editor of the Chemical News.

8ib,—It would appear from your Correspondent's letter in the Chemical News of April 12, that this great "sanitary problem,"—viz., the " deodorisation and utilisation of the sewage of towns," which has for so many years successfully puzzled the heads of all scientific investigators, and baffled all commercial enterprise, has at length been solved by the Sanitary Manure Company, Manchester.

Taking a great interest in sanitary matters, and having chemically examined samples of their manure, I beg to offer a few remarks respecting it.

The Company's works are not yet, I believe, sufficiently advanced to supply large quantities of the manure to the agriculturalists. It is, therefore, to be hoped that many improvements will be introduced into its manufacture, so as to produce a " really valuable manure," instead of that now sent out as samples, which contains 31*25 per cent. of moisture, and 34 per cent, of mineral matters insoluble in acids. Thus we commence with 65-25 per cent, of useless material. Of the remaining, 34*75 per cent, consists of organic matter, ammonia salts, phosphates of lime, iron, magnesia, carbonate of lime, and all other constituents soluble in hydrochloric acid, of the human excrement, urine, ashes, &c.

The only truly valuable fertilising agents in this 34*75 per cent, are:—Amrr.oniacal nitrogenous organic matter, yielding 1*20 per cent, of ammonia; and phosphoric acid, in combination with lime, iron, and magnesia (as insoluble phosphates), equal to 5*7 per cent, of insoluble phosphate of lime. The other constituents of the manure are scarcely worth the expense of transport, which is the most important desideratum with manufacturers of artificial manures.

Commercially speaking, the manure may be said to contain two valuable fertilisers, ammonia and phosphates, but, unfortunately, these exist in such small proportions compared with the useless matter associated—vix., moisture, ashes, &c.—that it is rendered necessary that large proportions of thia manure should be applied to the

soil before any really beneficial action upon the crops can be expected.

The deodorising process is the best that I am acquainted with, the manure being destitute of the offensive smell which accompanies most manures containing nightsoil. I believe this Company to have token a correct view of the great question of sewage, as their process will not only relieve our sewers and rivers from the nuisance so seriously complained of, but will make that which is now wasted valuable for agricultural purposes. If the Company would prepare their manure without the water, ashes, &c. (amounting to upwards of 65 per cent.), and were it supplied at a moderate price, it must create a demand from farmers. If this is found impracticable, then a corrective addition of bones, woollen waste, superphosphate of lime, animal matters, ammoniacal salts, and nitrate of coda, become necessary, in my opinion, before it can safely be asserted to be "a better and safer fertiliser than guano." The probability of this last clause I leave for more experienced agricultural chemists than myself to decide.

I trust the above remarks will lead the manufacturers of sewage manures a step in the right direction, by showing the necessity of preparing a richer fertiliser from sewage than has yet been produced. The admixture of ashes, rubbish, and water will assuredly withhold from them that support from agriculturalists and scientific men which is requisite to ensure remunerative success in this great sanitary enterprise.—I am, &c.

Feabnside Hudson, Analytical and Consulting Chemist. Laboratory, Corporation Street, Manchester, April 19.

Dangers and Detection of Carbonic Oxidt. To the Editor of the Chemical News. Sib,—Carbonic oxide burns with a flame; but I would advise " W." not to experiment too much on it, but get rid of the stove. It is not generally known that carbonic acid gas is as respirable as chloroform vapour, and is now much used for irritable cough, &c, as a remedy; but carbonic oxide produces sudden giddiness, and acts as a deadly poison by destroying chemically the blood-globules of human blood in the vessels. It was carbonic oxide (CO) mixed with carbonic acid (C02) that proved so deadly to the poor Hartley Colliery miners.

The physiological tests of carbonic oxide, I rather think, are more discriminative than the chemical ones. I am, &c,

Charles Kidd, M.D. Sackvillo Street, W. April I*.

Chemical Notices from Foreign Sources. 1. Mineral Chemistry. Cast iron.—MM. Minary and Resal have been experimenting on cast-iron for two years {Comptes-Rendus, t. liv., p. 212). They seem to have made the not very original discovery, that the object of the puddling operation is to burn off carbon; but some practical remarks are to be found in the paper, which, however, may not be new to all our readers. Grey or black cast iron, they say, containing no, or but little, oxide of iron, must have oxygen supplied in the refining by Besscmer's or some other process. The white crystalline cast-iron oi.ly requires a prolonged stirring. The granular white, containing a superabundance of oxide, is sooner refined, but never makes good iron. Bessemer's process, the authors say, should only be applied to grey irons. They mention, too, that the fusibility of iron increases with the proportion of oxygen it contains. Two crucibles, one with iron shavings only, and the other with iron sha-ings and a certain proportion of oxide of iron, were placed in a wind furnace. In the former, the shavings were only soldered together slightly; in the latter, they were fused to a button.

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II. OBOANIC CHEMISTRY.

N.»iitii«'»i» of «31nco»i«ie».—When one equivalent of trichloride of benzine reacts at 1600 on 8ix equivalents of acetate of silver in acetic solution for thirty hours, the resulting acetic acid will be found to hold a body which reduces Barreswil's solution. If the acetic acid be saturated wi'hcirbonate of sodo, and the solution is shaken up with ether, the etherial liquor on evaporation gives a roloured oil with a very bitter taste, and which reduces the cupro-potassic solution. This oil, says Rosenstiehl (Comptes-Rendus, t. liv. p. 178), appears to be a mixture of several glucosides; but heated on a water bath with dilute sulphuric acid, the glucosides most easily altered are destroyed, and on cooling small crystals are deposited. They are soluble in all sorts of solvents, have an extremely bitter taste, and reduce Barreswil's solution just like glucosides. When boiled with dilute sulphuric acid they evolve acetic acid. Their analysis led the author to construct the following formula to express their composition :—

Cl?

Two equivalents of the trichloride of benzine, and three equivalents of acetate of silver, treated in the same way as before, gave a body like a true fat. The author seems to have entered upon a very hopeful course of experiments, and thinks soon to obtain glucose itself.

III. ANALYTICAL CHEMISTRY. Erron In the Estimation of .\itrojrrn Iiy Combustion with Soda Limf. — K. Mulder points out (('Item. Ccntralblalt, 1862, s. 44) some sources of error in the method of Will and Van-entrap. The cork may absorb some of the ammonia, and if the hydrochloric acid in the bulbs is not sufficiently dilute, chloride of ammonium may escape with the hot steam. He recommends that the substance to be burned should first be mixed with soda lime in fine powder, and this mixture with a larger quantity of granulated soda lime. An ammoniacal salt must be first mixed with carbonate of lime. The cork he covers with tin-foil, and for a nitrogen apparatus he uses a 17 tube filled with fragments of glass moistened with hydrochloric acid. Dr. Knop remarks that the column of soda lime should not be too long, for he has satisfied himself that when the column is long and is too strongly heated, some of the ammonia is decomposed. The error, however, is always small.

MISCELLANEOUS.

CURIOSITIES IN CHEMICAL EVIDENCE.

DOWNING V. CHANCE.

From a letter which appeared in our last Number it will be seen that Mr. Alfred Bird denies the accuracy of the statements attributed to him in the leading article and report of the above trial given in the Chemical News of the 5th instant.

We have now befcre us a transcript of the circuit shorthand writer's notes, and we feel it necessary in order to vindicate our own and our reporter's correctness, to print that portion of Mr. Bird's cross-examination to which allusion was made:—

Mr. Serjeant Pioott: Q. Let me ask yon, in your judgment does the result of your experiment amount to this, that your test paper had received the muriatic acid, or hydrochloric acid gas, and nothing else? A. I am quite sure of that. Q. And that nothing else would have produced the same result? A. Nothing else. Q. Do you known what cyanogen is? A. Yes. Q. Would that h3Ve

produced the same result? A. It teas not necessary to look for it! Q. That is no answer, you know, to my question. Would it produce the same result ■ A. It might have thrown down a white precipitate. Q. If it might do so, would it do it? A. If cyanogen had been present.

Q. What would have been the appearance?

A. In the first place, there was ammonia in tie paper. Q. Would not the cyanogen have combined with that? Would it or not according to your analytical chemical knowledge? A. It might have combined if it were present. Q. We do not deal in mights; it either will or it will not. Will it? A. It might have combined with it if it were present. Q. All of us who know nothing about it could say it might, and could say it might not. We go to you learned men to say whether it would or not.

Mr. Baron Channell: What is cyanogen? A. Cyanogen is not a constituent of common suit

Mr. Sergeant Pioott: Will you tell me what cyanogen is? A. It it a compound of tico gases. Q. What two f A. It is a compound of nitrogen and hydrogen. Q. Is not it an element? Tell me what you say it is? I am told it is not an element. A. It is a compound of two gate*. Q. What two? A. It is a compound of two gases, nitrogen and ——. / cannot just refresh my memory a* to the other. Q. Is it nitrogen and hydrogen? A. The subjects are so entirely at variance with the existence of hydrochloric acid. Q. I admit they are difficult. A. We might assume the presence of fifty elements, and it docs not necessarily follow that I should be able at a moment's notice to give what they are composed of. Some of the compounds are so excessively difficult that it would be perfectly impossible without scientific books to enter into their composition. Q. Very well, that is an admission. Cyanogen can be analysed, and, inasmuch as you are an anal} ticol chemist, you can tell me what it is composed of, or cannot you do so? A. I rather decline to answer that question. It has nothing whatever to do with the thing, and I might perhaps make some little slip for which I have no doubt my friend at your elbow, who has got his dictionary with him, would be down upon me. 1 came here to prove the existence of hydrochloric acid. Q. That is very c; ndid indeed of you. A. If 1 take his place when he gets into the witness-box, perhaps I may catch him out.

Mr. Huddlebtone: We will have our dictionary and ask him some hard words, and ask him to define them. . . .

Mr. Sergeant Pioott: Chlorine is given off in the brick works in abundance, is it not? A. Yes, but I cannot say as to that positively. Q. Is cyanogen given off in the iron works? A, I believe cyanide of potassium has been found, therefore cyanogen may in some cases be found. I believe it is a matter of doubt whether it is always found. Q. You would not tell me what cyanogen was composed of before, you know? A. I declined to go into its composition. Q. Why did you decline? You have no conscientious motives, have you? A. No; on these sort of things you require to speak with absolute certainty; and being under cross-examination, it is evident that the smallest lapsus of memory might involve me in perplexity, and as I am quite certain it does not affect the merits of the case I should rather decline to go into it

When a practical chemist is capable of getting into the witness-box and exposing such ignorance of the principles of his science, there is little wonder that the evidence of experts is viewed with such suspicion by a jury.

ANSWERS TO CORRESPONDENTS.

Carol), or Locust Bean.—A correspondent wishes to bo referred to a reliable analysis of this bean.

D. Blackly.—We will refer to the paper and give you tho information as soon as found.

Book lUctivtd. "School Chemistry." By U. Dundas Thomjison, M.L>. Second Edition. London: Longmans.

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CHEMISTRY AT THE INTERNATIONAL
EXHIBITION.

The display of chemicals at this year's International Exhibition is the finest that has yet been collected together. Not only are the exhibitors more numerous than in 1851, but there are more first-class names on the list, hardly one manufacturer of eminence being absent. In our leading branches of chemical^'manufactures the show is wonderfully good, great pains having been taken by the Committees and the Superintendent of the Class to procure their adequate representation. The specimens of alkalies, alum, and the coal-tar dyes generally, constitute the great bulk of the exhibition. Looking hastily through the range of cases, wo meet the familiar names of Allhusen and Co., Chance Brothers, the Jarrow Chemical Company, Hutchinson and Earl, Musspratt, the Walker Alkali Company, Oaskell, Deacon, and Co., and several others equally famous in the manufacture of alkali. The samples sent by these firms are fine in the extreme, some of the soda crystals being almost perfect in form. When all are so good it would be invidious to choose; hut the samples of mono- and bicarbonate contributed by Hutchinson and Earl, and Gaskell, Deacon, and Co., appear to be as near perfection as they possibly can be. Mr. Peter Spcnce has sent a splendid cone of alum, weighing nearly five tons. A hole has been cut in the side in order to render the interior visible. Another cone of equal size and excellence has been contributed by the Metropolitan Alum Company, and forms the most prominent object in the trophy, which has been arranged by Mr. S. Howard, the Chairman of the Metropolitan Committee.and Mr. C. W. Quin, the talented and energetic Superintendent of the Class. Averyfinebut small crystal of alum, sent by Bray and Thompson, has already attracted great notice. In coal-tar dyes, Messrs. Perkin are of course foremost. Their collection illustrative of the manufacture of mauve is very complete. They are almost eclipsed in colour, although not in excellence, by Simpson, Maule, and Nicholson, who exhibit a magnificent crown of crystallised acetate of rosaniline, which presents the most dazzling appearance, and will soon rank amongst the lions of the Exhibition. In their wake follow Roberts, Dale, and Co. (who also exhibit some fine samples of oxalic acid prepared from sawdust), Rumney, Holliday, Dawson, Judson, Allen, and several others. Indigo and the lichen dyes are also well represented, the collections of Haworth and Brook, Pincoff, Wood and Bedford, Marshall and Sons, B. Smith and Sons, and Haas, being especially good. The collection of specimens illustrating the improvements made in dyeing and calico-printing since 1851, formed by Mr. R. Rumney at the request of Her Majesty's Commissioners, affords a wonderful proof of the activity displayed in this branch of chemical manufactures during the last eleven years. It includes the very fine collection of madder products formed by Dr. Schunck, and exhibited

by him before the British Association at Manchester last year. Other chemical manufactures are well shown; some sulphate of copper in gigantic crystals, by Buck and Co., of Manchester, a sulphate of iron crown, by Buckley's trustees, excellent specimens of prussiates, by the Hurlet and Campric Alum Company, bichromate, by White and Co., and prussiates, by Bramwell and Co.,— are extremely fine. In fine and rare chemicals, Huskisson's iodides, Morson's lithia and nickel salts, Foot and Co.'s acids, the iodine products by Ward and Co., and a series of interesting products by Hopkin and Williams, are only a few of the fine displays in this branch. Dr. Sten house, Dr. Miiller, and Mr. Church contribute interesting products chiefly discovered by themselves, the specimens of orceine and nitrotheine in the collection of Dr. Stenhouse being wonderfully pure and perfect. Mr. Crookes exhibits the new element, thallium, and several of its compounds. A series of bile products, by Bullock and Reynolds, are likewise very fine. Chemical colours and pigments receive adequate representation at the hands of Winsor and Newton, who send over 1000/. worth of real ultramarine; J. W. Smith, whose Magenta lake is extremely beautiful, and a number of others. Bailey exhibits some very fine porcelain colours, and Emery and Co.'s case of specimens of these materials is a perfect gem in the taste shown in its arrangement. Wilkinson and Heywood, Mander Brothers, Wallis Brothers, and Ilea, send some fine samples of gums and varnishes. Lucifer matches are well represented by five or six of the first houses in the trade; and the familiar names of Everett, Day and Martin, and several others, are here in all their sable glories. Laundry starch is contributed by nine or ten well-known houses, amongst whom may be mentioned Orlando Jones and Co., J. and J. Colman, S. Berger and Co., Broomhall, Wotherspoon, Rickett, Stiff and Fry, and many more. One of the great features in the class is the splendid collection of drugs formed by the Pharmaceutical Society, which fills one of the finest cases in the whole building. This case is really a model in its way in point of convenience and good taste, and does the greatest possible credit to the Society and its architect. Arrangements have been made by which any person can examine, feci, taste, and smell any of the drugs contained in the collection. Hanbury and Co. exhibit some very fine pharmaceutical preparations, which Ransom, AVatts, Bastick, Dickinson, Holland, Usher, and a host of others, try their very utmost to beat. The series of cinchona products by Howard and Sons could hardly have been produced by any other house. A magnificent mass of crystals of codeine, measuring eighteen or twenty inches in diameter, and worth upwards of zoo/., is exhibited by Macfarlan and Co., who also contributo some splendid specimens of anarcotine, morphia and its salts, sulphate of berberine, narceine, and other opium products. The trophy—which consists of a fine moss of alum crystals, surmounted and surrounded by crystals of prussiate, bichromate, sulphate

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of copper, and other chemicals, piled in artistic forms— was an impromptu affair resulting from a private conversation between Mr. S. Howard and Mr. C. W. Quin^ assisted by a sheet of blotting-paper and some very bad pens. The idea gradually grew until it has assumed its present shape. When completed, it promises to be a very magnificent mass of colour and form, and will attract a great deal of admiration even from the ignorant sightseers, who believe all chemicals to be acids, and all acids to be spontaneously explosive.

SCIENTIFIC AND ANALYTICAL CHEMISTRY.

(Conlinunl from page 116.) Researches of Pasteur respecting the Theory of Spontaneous Generation, translated and condensed by M. C. White, M.D.

fermentation of (Trine.—A flask with an attenuated neck was one-third filled with fresh urine and boiled for three or four minutes and then allowed to cool, with no access of air except what was drawn through a platinum lube heated to redness. When cool, the flask was hermetically sealed, and the enclosed urine was thus exposed only to atmospheric air, deprived by heat of all viable germs. In this condition the urine remained for months without change. Into a flask thus prepared, asbestos charged with atmospheric dust was introduced by the method above described. The flask was kept at 86° F., and in about six hours mucedines and infusoria appeared, among which were bacteria, vibriones, and monads, the same as appeared in similar urine exposed to the open air. During the following days lithates and crystals of triple phosphate were deposited, the urine became ammoniacal, ana its urea disappeared under the influence of the true ferment of the urine, which Pasteur believes to be organised, and whose germ could only have been introduced in the atmospheric dust in connection with the germs of infusoria and mucedines. When a flask prepared in the same manner had only calcined asbestos introduced, without atmospheric dust, neither mucedines nor infusoria appeared, neither did any fermentation take place, however long the flask was permitted to remain unopened.

Coagulation of Milk.—Fresh milk was boiled in a flask for two or threo minutes only, and after being allowed to cool with access of calcined air, as in the preceding experiments, it was hermetically sealed. In eight or ten days the milk was coagulated, but when opened it was found remarkably different from milk coagulated in the open air, for it remained alkaline as fresh milk; but the milk was filled with infusoria, most frequently vibrios about y^oth of an inch in length, yet no vegetable productions were detected.

The common theory that milk coagulates in consequence of the formation of lactic acid is an error. It is also shown that vibrios may appear in milk which has undergone ebullition for several minutes at 212° F., although urine or a solution of sugar and albumen does not produce vibrios under such conditions. In other experiments the milk was boiled for longer periods under a pressure of 1J atmospheres at a temperature of 230° or 235° F., and tho flasks were, sealed as before. Flasks thus prepared furnished no infusoria; the milk did not coagulate, however long it remained enclosed in the flasks; it remained alkaline even with the presence of oxygen in the form of calcined air, as stated above;

and it preserved apparently all the properties of fresh milk.

Into flasks of milk thus prepared, Pasteur introduced atmospheric dust by the method detailed above, when the milk coagulated, and both animal and vegetable productions appeared as in the milk exposed to the open air. The generally admitted theory of ferments which had of late years received fresh support from the writings of chemists, now appears more and more at variance with the results of experiments. The ferment is not a dead substance without determinate specific properties. It is a being whose germ is derived from the air. It is not an albuminous substance altered by oxygen. The presence of albuminous matters is an indispensable condition of all fermentation, because the "ferment" depends upon them for its life. They are indispensable in the light of an aliment to the ferment. The contact of the atmospheric air is, primarily, equally an indispensable condition of fermentation; but it is indispensable only as being a vehicle for the "germs" of the "ferments."

There are many distinct organised ferments which excite chemical transformations, varying according to the nature and organisation of the ferment.

To confute various objections made by advocates of spontaneous generation, Pasteur undertook to determine the relative abundance of organic germs in different localities. A series of flasks were all one-third filled with the same putrescible fluid,— a solution of sugar and albumen was employed in most of the experiments. The fluid was then boiled for two or three minutes in the flasks, and the neck of each flask was drawn out to a fine point, and hermetically sealed while the fluid was hot. These flasks were then taken to different localities, and the points of the necks were broken, and the air of the several localities allowed to rush in and fill the flasks. This violent ingress of air carried in, of course, all the dust held in suspension, and all other principles known or unknown associated with it. In this condition each flask was again hermetically sealed, and the whole placed where they were kept at a uniform temperature of 8o° to 850 F.,—a temperature known to be the most favourable for the development of animalcules and mucors. The results of these experiments were not what the principles generally admitted would lead us to expect, but they were perfectly consistent with the theory of the diffusion of germs.

Generally in three or four days the liquid in the flasks was found altered, but in flasks placed in identical conditions were found very different organisms,—much more varied so far as mucedines and torulas were concerned than if the liquids had been freely exposed to ordinary air. On the other hand, it frequently happened in a series of experiments that several of the flasks remained absolutely unaffected for an indefinite time, as if it had received only calcined air.

This simple and unobjectionable method of experimenting appears to demonstrate that the cause of socalled spontaneous generation docs not exist in the ambient air throughout its whole extent, but that it is possible to take up in a single place and at a given instant a considerable volume of ordinary air which, without having undergone any physical or chemical change, is altogether unsuitable to give origin to infusoria or mucedines in a liquid which is invariably thus altered when it is exposed to the open air. Tho partial success of these experiments shows that by these movements of the atmosphere there is always brought to the surface of a putrescible liquid in an open vessel a quantity of air

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