an opening th of an inch or more in diameter. In some of the flasks the liquid was boiled for several minutes, but three or four were not heated to the boiling point. All the flasks were then set away in a quiet place, free from currents of air. After twenty-four or forty-eight hours, according to the temperature, the flasks in which the liquid was not boiled after being put into them (although all the liquid had been boiled before it was put into the flasks) were found to be troubled and covered little by little with mucor. The liquid which had been boiled in the flasks remained limpid, not only for days, but even for entire months, although all the flasks were left open. There can be no doubt that the curves and sinuous forms of the necks served to secure the contained fluid from the fall of germs.

The common air entered these flasks as they were cooling, but so slowly during the gradual cooling of the hot liquid, that the germs were either destroyed by the heat or were deposited in the curvatures of the narrow necks of the flasks, so that no viable germs reached the liquid. When the neck of one of these flasks was broken off, and the remaining portion placed vertical, in a day or two the liquid became mouldy or filled with bacteria. This method, which so well explains the preceding, and which can be so readily practised by any one, carries conviction to unprejudiced minds. It gives also peculiar interest to the proof which it presents to us, that there is nothing in the air except its dust, which is a condition of organisation. It thus appears that oxygen acts only to sustain life furnished by germs, while of gas, fluids, electricity, magnetism, ozone, things known or unknown, there is nothing in the air except the germs which it carries which can originate organic life.

(To be continued.)

On Soil-Analysis, by Professor S. W. JOHNSON, of Yale College.

(Continued from page 199.)

We now come to Dr. Owen's fourth result of soilanalyses, viz., its power of indicating "the suitability of the soil for any particular crop." Closely related to this is the fifth item,-viz., that analysis can show "what

Produce per Imperial

Acre.

addition any soil, either uncultivated or cultivated, requires to render it productive and remunerative for any given crop; and, of course, the deficiency in the soil of one or more of the eleven elements determined by chemical analysis."

We cannot help feeling that the above assertions, which are here made unqualifiedly, were intended to be understood with a large amount of reserve, and subject to various conditions. Otherwise, we must regard them as quite unjustified, if not absurd. The chemical analysis of soil reveals nothing as to its tenacity or lightness, its porosity or retentiveness for water; yet these physical and mechanical conditions more than anything else determine the adaptation of a soil for any particular crop. The best grass lands are not the best wheat lands, and although it would scarcely be questioned that wheat requires a richer soil than grass in order to produce an average crop, and although, as we know, it often happens that many successive hay crops may be removed from a meadow without sensible diminution of the yield, while uninterrupted cropping with wheat nearly always reduces the capacity of the soil in a very few years below a profitable point; yet each average hay crop removes from a field more of every ingredient of vegetation than the grain and straw together of an average harvest of wheat. Such, at least, is the testimony borne by the most recent and trustworthy data. Dr. Anderson, of Glasgow, basing his calculations on the best analyses, and on the extensive agricultural statistics gathered in late years by the Highland and Agricultural Society of Scotland, makes the annexed estimate of the amount of the principal ingredients removed from an acre by average crops of seven staple British farm products (Trans. Highland and Agricul. Soc., 1861, p. 568).

On comparing the amount of matters removed from an acre by the wheat and hay crops, we find that the latter requires four times as much potash, lime, and sulphuric acid, twice as much silica, and one-fifth more nitrogen.

Again, we know that oats are raised on soils which are considered too poor for the profitable production of wheat, and the Table shows us that an average crop of oats requires more of every mineral ingredient than is necessary for a corresponding wheat crop.

In fact, wheat is the crop to grow which continuously

CHEMICAL NEWS, April 26, 1862.

requires, according to universal agricultural experience, land richer than that needed for any other of the seven crops whose chemical statistics are given in Dr. Anderson's Table, and notwithstanding, with the exception of barley and the potato tuber, it removes the least from the soil.

The farmer knows that wheat delights in a deep, rather heavy soil.-one which holds moisture well and yet is not wet. Barley and oats flourish on soils that are too dry and light, and grass on those which are too wet for wheat.

But how does the matter stand when these external conditions are taken into account? Does not analysis aid us then in a good degree? Let us take a case similar to what has repeatedly occurred in actual practice. We have a soil which, as the result of long cultivation or from natural deficiencies, is incapable of yielding a remunerative crop of wheat. Its texture is good, it has produced wheat abundantly, and needs nothing but a little of the right kind of manure to restore its power of giving a crop. We put upon it Peruvian guano at the rate of 300 lbs. per aere, and the harvest is a good one. The entire addition to the soil is but 300 one 3000006ths hundredth per cent. The amounts of phosphoric acid, of alkaline earths, and nitrogen added, are, for each, but butth per cent. of the soil taken to the depth of a foot. These quantities are rather minute for even the improved analysis of the present time to estimate successfully.

=

such land."

On page 230 of the Third Kentucky Report, Dr. Peter gives the analysis of this soil, and says:-"The inability of this soil to produce clover is explained by its very small proportion of lime, and rather small amount of sulphuric and phosphoric acids. The addition of plaster of Paris or some of the calcareous marls would probably restore it to the capability of supporting a clover crop.' The per-centage of the ingredients which Dr. Peter considers deficient are as follows:

Carbonate of lime 0'072 lime 0.040
Sulphuric acid
Phosphoric acid

0.055 0'070

Small as are these quantities, the smallest of them, viz., that of lime, yet amounts to 1200 lbs. per acre, which is enough to supply ten clover crops of three tons each, and as by the analysis it all exists in the form of carbonate, it must all be available. We know from the vegetation experiments of Boussingault, Ville, and Sachs, that plants are capable of absorbing from a limited

The mineral ingredients of plants.

227

amount of soil the whole of any soluble nutritive substance present, provided its quantity be no more than the plants require, and the other elements of fertility are at hand in excess.

(To be continued.)

Preparation of Formic Acid by means of Carbonic Acid, by MM. KOLBE and SCHMIDT.

A MIXTURE of bicarbonate and formiate of potassium is obtained in twenty-four hours by spreading potassium in thin layers under a receiver closed by tepid water, and into which an atmosphere of carbonic acid is introduced.

Sodium behaves in the same way, but the yield is less, The saline mixture is white. When neutralised by sulphuric acid and distilled, it evolves the formic acid, which boiled with carbonate of lead forms beautiful needles of formiate of lead.

No carbonic acid is produced when a concentrated solution of carbonate of potash is submitted to electrolysis.-Annal. der Chem. und Pharm., cxix. 251.

TECHNICAL CHEMISTRY.

Chemistry and the Manufacture of Iron.
No. I.

for Testing, Fire-bricks.—Composition Method &c.—As an analytical chemist, I have had much to do with ironmasters and blast furnace managers, and find that, although some of them are acquainted to a certain extent with chemistry,-these are very few,-the majority of them know little or nothing about it. The conse quence is, that an analysis of either the material used or produced is not so generally appreciated as it ought to be.

In three or more papers I shall endeavour to describe as fully as possible the chemistry relating to this manufacture, and to point out the importance of an analysis to those engaged in it.

Fire-bricks.—In this country fire-brick is generally used for constructing the furnace, and it is of the first importance that this should be of good quality. From an analysis of a brick, along with its physical appearance, an intelligent manager ought to be able to say whether or not it will answer his purpose.

A fire-brick, to be generally useful about blast furnaces, must not only withstand high temperatures without "running," but also the action of melted slag when at this temperature. Some bricks will stand almost any temperature if let alone, but when brought into contact with melted slag they fuse, or, again, if touched by the Workmen's tools they break easily; and hence, although very suitable for some special purpose where heat alone is required, they are generally of very little use indeed. A good fire-brick ought always to be very close, and possess a good specific gravity. Closeness of grain and density sometimes make up for a little inferiority in composition. Of course, I speak now of bricks that are to be exposed to chemical action as well as heat. Under other circumstances this is not of so much consequence.

Fire bricks generally contain silica, alumina, oxide of iron, and potash. Silica and alumina are the principal constituents; in fact, the more nearly the brick is free from the other bases the better it may be considered, because the greater the number of bases a silicate contains the more easily it is fused. For instance, a doub

silicate of magnesia and lime is more readily fused than either of the compounds alone. To a certain extent, also, the less the per-centage of alumina the better. The following table shows analysis of four fire-bricks, which differ much in composition:

Analysis of Fire-bricks.

NEWS

pieces of brick; they will be found to have been penetrated to different depths by the limestone; the one acted upon most must be considered the worst. Exposed in this way, Nos. 1. and III. were very little acted upon; No. IV. was semi-fused to about one-eighth of an inch in depth; and No. 11. to a quarter of an inch. (To be continued.)

100°23 99'44 100 42 100*76

No. 1. is a first class Stourbridge fire-brick. It was found to stand a very intense and long-continued heat. In the hearth of a blast-furnace it remained little acted upon by either slag or iron. By referring to the table, it will be seen that the per-centage of silica is very high; besides this only 2:49 per cent. of directly injurious bases are present.

No. II. is a very inferior Newcastle brick. When tried in coke ovens it was found to "run." In the cupola, too, it required so frequently renewing, that for this purpose it is now very seldom used.

No. III. is a brick made from a mixture of clay and sand. Owing to the very large per-centage of silica which it contains, it is well adapted either to stand intense heat or to be placed in positions much exposed to the action of slag. There is an opinion, which is held by some ironmasters, that a silicious brick is not calculated to withstand the action of a basic slag; there is a danger, they say, of the lime contained in the slag uniting with the silica of the brick and forming a fusible silicate of lime. Tried by an experiment, which I shall detail directly, this is not a correct opinion. The infusibility of the silica in a great measure prevents this action. Besides, a brick containing more base is much more likely to form a double silicate of lime and alumina, which, melting at a lower temperature than silicate of lime alone, would, in the same space of time, expose more surface to the action of fresh portions of slag.

No. 1v. is a sample of a very good Newcastle firebrick.

In the following manner the comparative value of a number of samples of bricks can be readily determined:Take a piece about one cubic inch in size from each brick, and fix them in separate plumbago crucibles with charcoal, in the manner shown in section in diagram; now cover both brick and charcoal over, to the depth of a

a. Fire brick. b. Charcoal packing. c. Limestone.

quarter of an inch, with limestone; the crucible must then be covered in the usual way, and exposed to the highest heat of the wind-furnace for an hour. After the crucibles are cool, break the lids off and examine the

Ammonia = Soluble phosphates equal to soluble phosphate of lime, 18.00 per cent.

Soluble salts (sulphate of lime excepted):

=

28-85 per cent. It is evident that, whatever theory we profess with regard to the fertilising action of manures, such a composition as the above must constitute a more valuable fertilising agent than Peruvian guano. This, in fact, has been found to be the case in practice. It is not sufficient to consider what elements are found in a manure; we must also take into consideration the state in which they are presented to the plant. Pure gelatine, though very rich in nitrogen, is no fertiliser; coprolites and bone-meal require to remain a long time in the soil before they become assimilable, and in certain soils where no acids are produced they never can be absorbed.

CHEMICAL NEWS, April 26, 1862.

}

PHARMACY, TOXICOLOGY, &c.

On the Preparation of Resin of Podophyllum,
by EDWARD PARRISH.

THE process for preparing resin of podophyllum consists in exhausting May apple-root with strong alcohol, concentrating the tincture, and throwing it into water to precipitate the resin; collecting, washing, and drying this. Upon each of these points a few comments are offered.

Exhausting the Root.-In my former experiments I used the steam-displacement apparatus invented by the late C. Augustus Smith, and found alcohol at the boiling point, used in this way, to produce a very concentrated tincture, though the use of the steam displacer involves a good deal of unnecessary trouble in small operations. For treating one or two pounds of the powdered root, which should be fine, a large funnel is convenient, the powder being moistened with a very little, say six fluid ounces of alcohol to the pound, and poured upon a plug of tow or cotton in the apex of the funnel, well shaken and packed after each addition. On a further addition of alcohol, the tincture passes, drop by drop, very strong, so that a pound may be thoroughly exhausted with from one and a-half to two pints. The proper point to desist from the addition of the menstruum is conveniently ascertained by dropping the percolate into water, when, if it contains an appreciable portion of resin, each drop will occasion a slight cloudiness.

Concentrating the Tincture.-In large operations it will be desirable to recover the alcohol, which may be done with very little trouble with a pharmaceutical still. In evaporating a pint or two of the tincture, an evaporating-dish on a sand-bath, or submitted to the regulated flame of a gas-furnace, will serve a good purpose. The extent of the evaporation is a point of importance, to determine which I have made a number of experiments. If the tincture is not concentrated enough, a considerable proportion of the resin will remain in solution when added to water; if too much, it will not mix with water sufficiently to produce a favourable separation of the resin; in the case of a recipe furnished with a view to its insertion in the Pharmacopoeia, I obtained threefourths as much resin on the partial evaporation of the liquid after the separation of the first precipitate as was precipitated on the original admixture with water. The best point at which to arrest the evaporation appears to be at from two and a-half to three and a-half fluid ounces of the evaporated tincture to each pound of the root treated.

Precipitating by Water.-The proportion of water to which the evaporated tincture should be added is not unimportant. I think four parts of water to one is, perhaps, most desirable. If the specimen of the root treated was highly resinous, and the extraction was very complete, the alcoholic fluid extract may be rather thick and even of a syrupy consistence at the degree of concentration above indicated. In this case it is better to add it to the water while hot and comparatively fluid. Collecting the Precipitate.-In some instances in which this process has been varied to test the eligibility of certain modifications, the resin has been so imperfectly precipitated as in part to pass through a filter, remaining suspended in the filtrate; in others, though arrested by the filtrate, it could be only partially separated after drying; in no case could it be successfully collected by subsidence; so that several experiments were made to

229

find the best method of collecting it. The most successful of these consisted in heating the whole aqueous liquid, as contained in the precipitating vessel, in a water-bath till, just below the boiling point, nearly all the resin was fused and collected on the bottom and sides of the jar; then by a spoon or spatula the main portion could be collected together, and by rotating the mass all adjacent particles could be made to adhere to it. The "Eclectics are in the habit of adding muriatic acid to the water to aid the separation of the resin. I have found this highly advantageous, both with reference to collecting the precipitate as only partially separated by water alone, and to procuring the remaining portion after the more completely separated precipitate has been removed. There is an objection on the part of some to such an addition, under the supposition that the change must be a chemical one, but I observe no difference between specimens, whether collected with or without this addition, and am inclined to attribute the more complete coagulation of the particles of resin under the influence of the acid, which may be used in very small proportion, to a mechanical rather than a chemical alteration.

The Drying of the Precipitated Resin in powder is not a very easy matter. It is rather unsuitable to wrap in paper, especially where artificial heat is to be used, which is apt to fuse it and occasion its absorption by the paper. In one case in which it had been collected on a filter, I was obliged to re-dissolve it in alcohol, and then pour it out on plates of glass, in the manner directed for citrate of iron. It was readily scraped off from the glass, but was not in handsome scales. If collected in mass by fusion under water, as above described, it may be kneaded and pulled so as to wash it thoroughly and lighten its colour, and may thus be dried without the least difficulty by wiping with paper and exposing to the air at ordinary temperatures. If prepared in powder it is readily reduced by trituration. I prefer it in lumps or pieces, in which condition it is more characteristic, and resembles resin of jalap of the shops. It is more characteristic, and less liable to sophistication or adulteration, when in the condition of broken mass, than in that of powder in which it is usually sold.

The Yield, by the process described, varies from three to five per cent. of the root. There is, perhaps, always some loss in the course of the process, which is proportionably less in operating on large quantities.— American Journal of Pharmacy.

Process for the Extraction and Investigation of Poisonous
Alkaloids, by MM. V. USLAR and J. ERDMANN.*
On the Characteristic Reactions of some Poisonous
Alkaloids, by M. J. ERDMANN.†

On some Characteristic Reactions of Nitric Acid, by
M. J. ERDMANN.

MANY difficulties attend the extraction of an alkaloid when, as in medico-chemical researches, it is associated with other organic matters. The following is a method recommended both by its simplicity and its generality. It is founded on the following facts:

1. Free vegetable alkaloids are soluble in amylic alcohol, especially by aid of heat.

2. Pure or alkaline water does not remove the bases thus dissolved; but,

* Annalen der Chemie und Pharmacie, vol. exx., p. 121. Ibid., vol. ex., p. 188.

Ibid, vol. cxx., p. 193.

3. It separates them completely when it has been previously acidulated with hydrochloric acid, the organic chlorides which are formed being almost insoluble in amylic alcohol.

The following is the method of operation:-Reduce the suspected matter into a pulp with water, slightly acidulated with hydrochloric acid. Then leave it to digest for two hours at a temperature of from 60° to 80° C.; pass a wet cloth over it, and exhaust the residue with acidulated warm water, and after mixing the liquids add a slight excess of ammonia; concentrate over an open fire, and dry in a water-bath. After exhausting the residue with warm amylic alcohol, filter it through a paper previously moistened with amylic

alcohol.

The filtered product is generally mixed with fatty or colouring matters, which must be eliminated by quickly shaking up the liquid with almost boiling water, acidulated with a little hydrochloric acid. The amylic alcohol then yields the alkaloid, while it retains the greater part of the fatty or colouring matters. Draw it off by a small india-rubber pipe, $ then shake the warm aqueous liquid with a fresh supply of amylic alcohol, and the foreign matters will be got rid off without much trouble, so that the acid solution containing the alkaloid in the state of hydrochlorate is completely decolorised. Slightly concentrate this solution, add a slight excess of ammonia, and then amylic alcohol, which after repeated shakings takes up the alkaloid.

After duly separating the two layers of liquid, withdraw the upper one, containing alcohol and alkaloid, and attack the lower layer by adding a fresh portion of warm amylic alcohol; then mix the alcoholic liquids and evaporate them by a water-bath, and the residue is generally pare alkaloid. If it has preserved its colour, the operator need not continue the operations just described; that is to say, dissolve in hydrochloric acid, shake with amylic alcohol, and draw off by a small pipe; supersaturate with ammonia, shake with amylic alcohol, and eliminate it by evaporation in a water bath.

It is very seldom that the alkaloid is not completely purified by this treatment; should it not be, the process must be repeated. ||

The authors have verified their process in various ways. Hydrochlorate of morphine mixed with panada, or putrid meat, exposed to the sun for fifteen days, was integrally detected by the special reaction it gives with sesquichloride of iron; nevertheless, the experiment was tried with less than a decigramme of hydrochlorate, mixed with 1 or 2 kil. of organic matter. The different portions employed varied between o'054 grammes and 0'005 grammes.

They have also recovered a drop of nicotine and two drops of coniine respectively added to 750 grammes of panada.

The same with 9 milligrammes of strychnine, 8 milligrammes of narcotine, as well as with a mixture formed of 0.012 grammes of morphine and oo13 grammes of narcotine mixed with a pulp of vegetables and meat, and left for four days to putrefy.

The alkaloids when recovered were separated from each other by ether.

§ This precaution is essential to prevent the inhalation of the vapours of anylic alcohol.

To all acquainted with the alteration produced in nicotine and con iine by the presence of air, it will be difficult to understand how alkaloids can escape the causes of decomposition to which they are exposed during this process, which not only does not protect them from the action of the air, but exposes them to it in presence of ammonia at the temperature of a water-bath,

On Fermentation as a Cause of Various Diseases, by M. POLLI.

CHEMISTS who have for several years been successfully studying the phenomena of fermentation, have observed that this mode of reaction, among organic principles, possesses an importance much greater than is generally supposed. It is, in fact, to fermentation that the spontaneous decomposition of animal and vegetable tissues is owing, as dry rot, eremacausis, gangrene, &c., and the whole series of successive transformations which organic matters undergo until they are converted into water, carbonic acid, ammonia, and mineral matters. It is by 'ermentation that fatty bodies give glycerine; that salicine furnishes glucose; that myronate of potash is converted into essential oil of mustard; that neutral substances, such as urea and allentoin, form ammonia; that amygdaline produces the poisonous substances,-oil of bitter almonds and Prussic acid.

Ferments act by contact or by catalysis. Sometimes they are living creatures; sometimes very active unorganised substances. Diastase, emulsine, and pepsine act as ferments. They can cause organic substances to double, become hydrated, or isomeric.

According to M. Polli, there exists considerable analogy between the processes of fermentation and several organic metamorphoses which take place in certain maladies: an albuminoid matter which, in a certain deteriorated state, acts as a ferment, and particular substances preceding from its action.*

But analogy is insufficient. It has been shown by carefully made experiments that the composition of the blood during disease undergoes alterations and variations; and that artificial disease, closely resembling natural ones, can be produced by introducing into the bloodvessels substances acting as ferments. Multiple abscesses induced by injecting pus into the veins of dogs; septic affections caused by the injection of purulent putrid matters into the veins of animals; diseases with all the characteristics of typhoid fever provoked by the injection of putrefied blood into the circulating current; finally, contagious diseases, such as the glanders, which are produced by injecting glandered humours, prove that a general affection can be simply produced by introducing into the blood a substance to play the part of a ferment. There are diseases produced by morbific ferments, which may be called catalytic maladies, in which the morbific matter, inducing metamorphoses by contact with the alterable principles of the blood, is the primary cause of all the symptoms presented by the animal economy. It is impossible to deny that fermentation takes place in the blood.

Admitting that the starting-point of many diseases is the action of a specific ferment in the blood, is it possible to prevent its effects to render it inactive in the living organism, as can be done by chemical means outside the body? This is the cardinal point which gives interest to this pathological question.

M. Polli believes that he has proved, by a series of facts and conclusive experiments, that it is possible to neutralise morbific ferments in the blood of animals by chemical substances which do not act in a manner incompatible with life; aud that with these substances it is we must hope successfully to treat discases of which fermentation is the primary cause.

* M. Pasteur says that the ferment is not an albuminous matter altered by oxygen, but an organised creature of which the germ is brought by the air; and that the presence of albuminous matter is a condition indispensable to all fermentation, because these substances are necessary or the development of the ferment.