HOW PEOPLE ARE POISONED. THE excitement that prevailed some years ago, with regard to the subject of poisoning, seems, like most modern popular emotions, to have soon pa sed from a condition of exaggerated magnitude, to one of unreasonable disregard. The only result of all the declamation, the controversy, the squabbling, and the gossip bestowed upon this subject was, that nothing was done towards remedying the evils that were on all sides admitted to exist in connection with the sale and use of poisons.

Meanwhile, the papers from time to time report the occurrence of cases of poisoning, both intentional and accidental, with a frequency that leaves little ground for the belief that the safeguards against poisoning are, to to say the least, any greater now than they were some years ago, when every one had the fear of poison before his eyes.

Without at all desiring to excite a poison panic, it may at least be asked whether the accumulated evidence of danger and disaster, arising from the sale of poisons, and the absence of any general system of protection against those results, is not a great anomaly at the present time and in a civilised country?

The subject is one undoubtedly of very great difficulty in many respects, but that is no reason whatever that it should be left alone; it is, on the contrary, rather a strong reason that it should be taken vigorously in hand, and dealt with somehow and to some extent. It will not do to wait in philosophic contemplation of how people are poisoned, with the object of devising an unobjectionable and perfect system to regulate the condition under which poisons are to be obtainable and to be used. Some step in advance, towards a protection against the possibility of poisoning, even if inconvenient in practice, would at least afford a better opportunity for devising and adopting more suitable mears of arriving at the results desired.

The common use of a variety of substances, which. if they cannot be called poisons in the strictest sense of the word, are, at least, of so deleterious a nature as to demand an exercise of caution in their use, is now much greater than ever it was, and in itself constitutes no trifling ground for legislative enactments in regard to the use of these substances. It would be unreasonable to prohibit or impede the use of oxalic acid any more than the use of Epsom salt; the one is as much a necessary commodity as the other, and should be as readily obtainable. Of course it is desirable that when one asks for Epsom salt he should not be given oxalic acid. That danger may be provided against by restricting the sale of such dangerous substances as oxalic acid to persons capable of distinguishing them from others that are harmless but similar in appearance, as Epsom salt is to oxalic acid. But this is a very partial protection at best; the intelligence of the vendor of dangerous materials is no safeguard against the

stupidity of the purchaser. It is, doubtless, a very great desideratum to raise the intellectual and educational standard of druggists, but that alone is no remedy for the evils resulting from the misuse of poisonous substances. An intelligent and well-qualified druggist may cause a stranger much trouble to obtain twopenny worth of oxalic acid or of arsenic, while he supplies without hesitation the same substances to a customer whom he knows to be a strawbonnet cleaner, or the ratcatcher's wife. It is after this point is passed, that the great danger of poisoning begins. The druggist may with all propriety have put on the packet of oxalic acid or arsenic, the label "POISON " without in the least contributing towards preventing the misuse of these substances by persons who can neither read it nor distinguish between arsenic and soda, or between oxalic acid and Epsom salt. It is in the misuse of these drugs that the mischief lies, and in this respect there is a vast difference between Epsom salt and oxalic acid. While the consequences of misuse, in one case, might be only incon venient, in the other, they might be fatal.

A striking illustration of this has just been afforded by the accidental poisoning of a lady near Tunbridge Wells. Being in the habit of taking a solution of mag. nesia, she sent her servant about daybreak to fetch her a wineglassful, which she drank, and feeling a burning sensation, asked the servant to fetch the bottle it was taken from. That told her she had swallowed chloride of zinc. Instead of "Dinneford's fluid mag. nesia." the servant had filled the glass with "Disinfecting fluid." Within twenty-four hours she was dead. The jury returned a verdict of accidental death from the effects of a dose (sic.) of Sir William Burnett's disinfecting fluid, given for a dose of Dinneford's fluid magnesia; and they expressed their strong disapprobation that a mixture, of such a poisonous nature as the former, should be sold without being legibly labelled with the word "Poison."

It might have seemed harsh, though not altogether unreasonable, to have added to this opin on a censure of the negligence which was manifested by the fact that the two bottles were kept together on the same shelf, although they are described as being "exactly alike in size and form, and in the colour, both of the glass and the liquid," but containing substances so vastly different -a simple medicine and a powerful corrosive poison. It is very difficult to say how such cases as this can best be met. People may insist upon having a right to keep poison and physic together, and claim a right to the consequent risk of being poisoned. It would be difficult to prove them in the wrong. But when such a practice becomes fraught with risk to others who have no such crotchet, and who may become unwilling victims to it, there can be no doubt that such a mad confusion of the aids of living with the agents of death, is in the highest degree reprehensible, and equally culpable, whether it be done deliberately or from carelessness.

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SCIENTIFIC AND ANALYTICAL CHEMISTRY.

Action of Sulphur on

Saline Solutions having an Alkaline Reaction.

M. J. DE GIRARD* has observed that by boiling a solution of soda pyrophosphate with an excess of wellwashed flour of sulphur, the liquid rapidly becomes brown, in consequence of the formation of a polysulphide. By continuing the ebullition for several hours, hydrosulphuric acid is abundantly evolved. The liquid gradually becomes colourless, meanwhile disengaging hydrosulphuric acid. The filtered liquid contained soda hyposulphite and a salt of phosphoric acid. Silver nitrate solution was added as long as the white precipitate, first formed, was rendered black by the formation of sulphide, and after separating this precipitate the filtrate gave a yellow precipitate with the silver solution.

A solution of sodium sulphide boiled with excess of sulphur evolves hydrosulphuric acid, and when the liquid has become quite colourless and neutral to test-paper, it contains only soda hyposulphite. Under the same circumstances, sodium sulphide alone, decomposes water at 100° C., evolving hydrosulphuric acid.

Water boiled with washed sulphur is also decomposed with evolution of hydrosulphuric acid.

Density of Vapours at Elevated Temperatures, by MM. SAINTE-CLAIRE DEVILLE and TROOST.†

(Continued from page 254.)

All the compound substances which give eight volumes of vapour consist of four volumes of one constituent combined with four volumes of the other, including among them phosphorus perchloride, if the hypothesis proposed by M. Cahours be adopted.

It has been assumed lately that the equivalents of these substances really correspond with four volumes of vapour, but that their constituents are separated at the moment when their vapour densities are taken, and then correspond, only in appearance, with eight volumes. MM. Deville and Troost consider this hypothesis to have little foundation in fact, and, in addition to the known facts that render it inadmissible, they made some further experiments to demonstrate their view.

1. Ammonia hydrochl rate is not decomposed at a temperature which is sufficient to decompose ammonia in great part. To prove this, two tubes, one closed at one end, and containing sal-ammoniac, the other having a current of ammonia passed through it, were both heated side by side in the same furnace. While the vapour of sal-ammoniac presented no sign of decomposition, the gas issuing from the other tube consisted of

Ammonia.

Nitrogen and hydrogen

*Comptes-Rendus, lvi., 798.

↑ Comptes-Rendus, lvi., 891. Vide CHEMICAL NEWS, vii., 243.

CHEMICAL NEWS, June 6, 1863.

When the temperature was increased, the gas issuing from the tube containing sal-ammoniac consisted of— Observed. Calculated.

Hydrochloric acid Hydrogen

Nitrogen.

nitrogen, and hydrogen, passed through a tube heated It was ascertained that a mixture of hydrochloric acid, to redness, does not give rise to the production of salammoniac even when the tube contains spongy platinum.

It is therefore impossible to suppose that sal-ammoniac was decomposed and reproduced in the experiments made to estimate the density of its vapour.

Similar experiments with ammonia hydrobromate and hydriodate led to the same result.

2. Ammonia hydrocyanate, which is produced at very high temperatures by the contact of ammonia and carbon, gives eight volumes corresponding with one equivalent; if it were decomposed it would not yield a mixture of ammonia and hydrocyanic acid, both of which would be decomposed before the hydrocyanate. §

3. Ethylamine hydrochlorate was to some slight extent decomposed, yielding hydrochloric acid and ammonia, in the experiments made to estimate the density of its vapour. These gases did not recombine. Deville and Troost to be evidence of the importance of These experimental results are considered by MM. Gay-Lussac's law, and of its general applicability; to show what a happy influence has been exercised on chemical doctrines by the introduction of the methods proposed by Dumas and Mitscherlich, and which they have followed as closely as possible. The consequences of the accurate observations of M. Cahours are manifest throughout these results; they are entirely confirmed by the numerical data obtained by MM. Deville and Troost. Moreover, the rule laid down by Gay-Lussac as to the contraction of compound substances, calculated

§ Hydrocyanic acid is decomposed at a dull red-heat into a mixture of cyanogen and hydrogen with a slight deposition of carbon. When the cyanogen is separated by means of potash, the gaseous residue is found to consist of

Hydrogen Nitrogen

The quantity of nitrogen increases with the temperature at which the gas is collected.

change will ensue beyond a faint violet-coloured line at the point of contact of the two fluids. A grain of chloride of sodium being added, a brisk effervescence runs throughout the sulphuric acid from the evolution of chlorine, which somewhat increases the violet colour, but on projecting the merest particle of a solid nitrate (say nitrate of potash) it will, on falling, carry with it so much of the pyrogallic acid as to be reacted on by the nitre and produce an intense purple colour, which, gradually mixing with the upper layer of the pyrogallic acid solution, gives off streaks or rings of orange-yellow, by becoming oxydised at the expense of the decomposed nitric acid of the nitrate. On the other hand, if the nitrate be first mixed with two or three times its bulk of chloride of sodium, and then projected through the pyrogallic acid liquor to the sulphuric acid below, no purple colour is produced, but the resulting effervescence causes the evolved nitrous acid to act more uniformly on the whole of the pyrogallic acid, imparting a deep orangebrown colour.

Such is the sensibility of this reaction, that even a drop or so of a solution of a nitrate added to the pyrogallic liquor previous to the projection of the chloride of sodium suffices to show the discolouration caused by the liberated nitrous acid, the intervention of the chloride of sodium, from the smallness of the nitrate, being necessary to its production, and renders it more evident than when the nitrate is used alone. Only part, however, of the drop of nitrate solution which comes into contact with the sulphuric acid will be decomposed, and even that is sufficient to give an intense colour.

The nitrous acid evolved from nitrates by heat or otherwise is also detected in its dry state by the discolouration of a piece of white paper moistened with a tolerably strong pyrogallic acid solution.

In fine, I am of opinion that this method of testing for nitrates and nitrites is far more delicate than any at present in use. Simple, easy of execution, and perfectly unobjectionable.

It is desirable that a piece of white paper should be placed at the back of the test-glasses, in order to show the reaction best, and also that no more chloride of sodium be used than is necessary, or equal to the sulphuric acid, so as not to lay undecomposed at the bottom of the glass.

Preference would appear to be given to the use of the dry salt with the chloride of sodium rather than a liquid

nitrate.

TECHNICAL CHEMISTRY.

The Chemistry of Agriculture.

(Continued from page 258.) Baron Liebig gives the following history of the "mineral theory," for the purpose of elucidating the principles on which his views were founded, and of enabling his readers to judge of the opinions that have been expressed with regard to it, and of the opposition it has encountered during the last twenty years.

The fundamental principles of his theory were:That the food of plants are inorganic or mineral substances, carbonic acid, ammonia, water, phosphoric acid, sulphuric acid, &c., &c.

That there is a connection between all the constituents of the food of plants, of such a nature that, when one is wanting, the others are insufficient to support plant life.

CHEMICAL NEWS, June 6, 1863.

That farm manure does not act by virtue of its organic portion, but indirectly by the products of its decay, by the conversion of its carbon into carbonic acid, of its nitrogen into ammonia.

These principles were in direct opposition to all previous views.

In regard to the source of the carbon in plants, the view universally received was that of De Saussure, who considered the absorption of carbon from carbonic acid, by plants, to be unquestionable, but in the case of cultivated plants he held that the principal part of their carbon was derived from humus, and from the soluble organic substances in the land.

The truth of this view was not proved, and upon the examination of the evidence on which it rested, it appeared to Baron Liebig to be incapable of proof. The demonstration of his own view involved no experiment, but merely a consideration of the natural relations of plants to the atmosphere and to plants; by comparing the phenomena of plant life with the chief functions of animal life, with respiration, and the constant amount of oxygen in the atmosphere, it appeared from the cyclical changes of oxygen that carbonic acid must be the only source of the carbon in plants. This view is directly and undeniably demonstrated by the late experiments of Knop and Stohmann.

Baron Liebig claims to have been the first to put forward the opinion that ammonia is the source of the nitrogen in plants, as a result of his researches on the phenomena of animal life, and of his knowledge of the changes that all nitrogenous organic substances undergo in decay.

He denies the accuracy of the remark in Schleiden's "Botany," "that De Saussure first sagaciously propounded the idea that ammoniacal salts are the source of the nitrogen in plants, and that Liebig subsequently developed this view." He states that De Saussure says nothing, in his work, of ammonia as a source of nitrogen, and that he elsewhere distinctly expressed the opinion that of all possible sources of nitrogen, ammonia was not one, opposing Liebig's view that it was assimilated by plants, and referring its value in vegetation to its solvent action on humus.

No special importance was assigned to nitric acid by Baron Liebig, only because he knew the nitric acid in soils to be always a product of the oxidation of ammonia. Hence he considered it capable of replacing ammonia as plant food.

De Saussure was the first to point out the necessity of lime phosphate for the development of plants, but his opinion received little attention. He had also investigated the question of the necessity of lime, potash, and magnesia, but unfortunately his investigation was limited to plants in which the amounts of potash, magnesia, and lime vary according to the land they grow upon.

The opinion that the alkalies and alkaline earths in plants are not accidental, but part of their food, is often asc ibed to Sprengel, who regarded all the ash constituents of plants as necessary or useful for their growth. His opinion received little attention either in science or practice, since De Saussure's observation that plants take up by their roots all kinds of saline solutions, was supposed to show that the presence of ash constituents was not a proof of their being necessary.

The circumstance that rendered Sprengel's opinions unproductive of any results, was his ignorance of the composition of plant ashes. He assumed that in most cases they were the same as in wood ashes.

The necessity of these substances could not, in Baron

Liebig's opinion, be inferred before the special functions or relations of each ash constituent, in plant life, were known, except from other unquestionable relations, such as the functions of the ash constituents of plants in animal nutrition. If these substances were indispensable for animal life, they must, it was inferred, be indispensable for plant life, since, if they were only accidental in plants, animal life would have been endangered by a change of them.

Among the opponents of Baron Liebig's doctrines as to the source of carbon and the phenomena of animal and plant life, were Moleschott and Mulder, and he reproaches himself with not having paid more attention to the views of these men than their real importance demanded, for, as teachers in universities, both exercise a wide influence, and hence Baron Liebig's views are regarded in Holland as untenable, and having been disproved by Professor Mulder.

Baron Liebig refers to the investigation of frog's flesh by Professor Moleschott as illustrative of his scientific status, and characteristic of many physiological and agricultural researches. The conclusion to which he came from his observations, was that the liquids of frog's flesh contain oxalic acid and urea-substances that had not been observed in the liquids of any other flesh. But he found no creatin, creatinin, inosinic, or lactic acid, which are present in other flesh liquids. Soon after it was shown that what Moleschott had taken to be oxalic acid was phosphoric acid, and the crystals he took to be urea nitrate were potash nitrate. Grohe also found that frog's flesh contained, like other flesh, creatin, &c. Commenting upon these results, Baron Liebig remarks that, in like manner as it is impossible to understand a book written in a foreign language without a knowledge of that language, so it is impossible to understand or judge of chemical phenomena without a knowledge of what they signify. A person who is unable to distinguish between the best known and most easily recognisable substances, by means of their reactions is regarded by the chemist as having no more claim to attention in chemical questions, than one unable to spell the words of a language, would have to give an opinion as to the meaning of a sentence in that language. To mistake phosphoric acid for oxalic acid, or potash nitrate for urea nitrate, are inexcusable errors, that show a total unacquaintance with these things.

It is obvious, says Baron Liebig, that it is not competent for any one who may take it in his head, to make a chemical experiment; this requires a capability that must be acquired by long practice, and which is very rare. Hence it follows that an inexperienced person even in simply repeating experiments will never obtain the results that are described, and, in making experiments of his own devising, he will never obtain the results he should obtain. If, in addition to this, there is a certain degree of vanity, he will, since he obtains different results, believe that he has disproved facts which are incapable of being disproved; or he will believe he has discovered new facts that exist only in his imagination; the opposite results to which he comes are so much the more striking, and the discoveries he makes are so much the more astonishing the more uninformed and incapable he is.

Agriculturists are in the same position with regard to chemistry that Professor Moleschott is, in regard to questions of physiological chemistry. It is quite impossible for a farmer, who does not possess any knowledge of chemistry, to understand rightly the explanation of chemical operations, or the significance of the facts relating to it; when

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such a man attempts to make experiments for the purpose of testing the accuracy of chemical facts, it is at once apparent that he really does not know what it is he is about; the question he endeavours to answer, is not clear to him, and, under such circumstances, even the most strenuous efforts cannot lead to a rational conclusion.

The worst of it is, that the multiplicity of facts, whencesoever they may be furnished, are to him of equal value, and that he does not know how to distinguish truth from error, or the valuable from the worthless. The greater the heap of facts the more significance he attaches to them; like a child, who has heard that gold rings are sometimes found in muckheaps, he believes there is treasure hidden in every muckheap. A sensible person seeking a guide in a strange place, would certainly choose one who knew the place, and had often travelled that road; but to the foolish, any one who offers himself will suit, and it is no wonder if he gets into a bog. In illustration of Professor Mulder's scientific ability, Baron Liebig refers to the protein researches, and to the results of Fleitman and Laskowski, showing that this substance did not exist, and that its discovery was a delusion. Baron Liebig says he fell into the error of believing that Professor Mulder would thank him for communicating these results, but his reply showed Baron Liebig that he had become his enemy for life, and would do all he could to show that Baron Leibig was a great sinner, though he gave him fourteen days to retract the opinion that the unfortunate protein did not exist. This he could not comply with, and Professor Mulder afterwards fell into the pitiable predicament of strengthening the evidence of the non-existence of protein, by means of two memoirs intended to demonstrate its existence. Since then enmity has existed, and in Professor Mulder's late work he has dwelt upon the insufficiency and defects of Baron Liebig's experiments on soils, but Baron Liebig, admitting those imperfections, laments that the suggestions of Professor Mulder have produced no good effects on him.

In reply to Professor Mulder's opinions as to the illogical nature of the alteration in the views held by Baron Liebig some years since, he admits that such is the case, and pleads as an excuse the progress of chemistry, and the necessity of a continual condition of moulting (deplumatio; la mue) in the chemist who wishes to keep pace with that progress. When new feathers grow, the old ones fall out of the wings, which will no longer carry him, and, after that, he flies so much the better.

Baron Liebig believes that a man like Mulder car derive but little true gratification from science, since he consumes his time and talent in the unproductive labour of exposing, in the careful and painstaking labours of others, the weakness and deficiencies that belong to all men's work. Those who labour much are naturally more liable to be so criticised; the fame of having fallen into no errors, belonging to those who do not labour, is not particularly enviable.

In conclusion, Baron Liebig refers to a biography of Professor Mulder, which relates that he could not understand the chemical lectures during the first year of his studies-a circumstance which troubled him, but did not repel him from the study of chemistry, in pursuit of which he learnt by heart Orfila's " Elements of Chemistry," and afterwards the first volume of Thenard's " Manual," certainly a singular way of qualifying himself as a chemist; but one Baron Liebig thinks which explains much that he has done.