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cluded that the deceased had not taken any dose of eliminate the poison. I had first of all to find what subeither of these poisons for at least three weeks before her stances were with the poison, and then to take the proper death. In his opinion, therefore, her death could not solvents to remove those matters. I wrote to be supplied have arisen from poison. The symptoms mentioned by with the symptoms—as I always do-immediately I reDr. Barclay were just such as antimony or arsenic would ceived the box. If I had not had the symptoms I should cause; but the result of the analysis showed that those have had a great deal more difficulty in finding the poisons were not administered. Death could only be poison. Perhaps I should not have found it at all. The attributed to those poisons when traces of them were poisons are divided into several classes, and the symptoms found. Dr. Barclay said that, after hearing the result would show me which of these classes I should test for. of the analysis, he could only attribute the deceased's It would be useless for me, as there are at least 200 death to natural causes. Dr. Taylor, in answer to the poisons, to commence a series of experiments which coroner, said that Professor Rudersdorf, of Holland, took might exhaust the material long before I had finished the part in the analysis, and he was of the same opinion as tests. In the interval between the Wednesday and the witness--that no arsenic or antimony could have been Sunday my tests gave me indications of one of the three taken by her for weeks before her death, and therefore cerebro-spinal poisons—atropine, daturia, and aconitina they could not have caused death. The coroner having - but the matter was not sufficiently clear of foreign summed up, the jury returned a verdict of "Death from mixture to be quite certain. · Atropine and daturia, natural causes.

though prepared from different plants, are the same poison. The Case of Reputed Poisoning by Atropine. I believe atropine has never been eliminated from an -The trial of Mr. Sprague took place at Exeter on the animal substance before. It has never been communicated first of this month. We give only Mr. Herapath's before to the scientific world, but it is now through my evidence. He said: I am a professor of chemistry, re- evidence, and I shall be put on my trial quite as much siding at Bristol. On the 19th July I received a wooden

as the prisoner. The poison, I think, must have been put box, corded and sealed. The seals were intact. In the in the pie while making, or on something that was put box was a pie-dish, which I produce, with its contents. in the pie.. I cannot say whether it was put in before or There is in it the fore leg of a rabbit and a small piece of after the pie was cooking. The crust might have been beef. The meat when I received it was not putrid." When lifted while it was hot, and the atropine put in; but my meat is cooked it decomposes in a different way. While idea is that it was put in before the pie was cooked, and the albumen is in a soluble state you get sulphuretted dissolved in the cooking. hydrogen and ammonia liberated; when the albumen

The cross-examination of Professor Herapath was probecomes solid by cooking, the meat dries like a mummy tracted to a great length, but without eliciting anything and becomes covered with mould, which is not poisonous. more of a material character, or shaking the learned genIn the box was also a jar with vomit and a parcel of tleman's positive testimony that there was atropine in the flour. I first wrote for the symptoms to give me some pie. The prisoner was acquitted. In reference to this clue as to the mode I should pursue ; but before I had

case Dr. Ogle has written to the Times mentioning some the arıswer I received a letter stating that it was right experiments of Runge, who found that rabbits could I should know that a mustard emetic had been given to feed on belladonna leaves without being poisoned. one party, and sulphate of zinc and ipecacuanha to the To Prevent Oaken Barrels from Colouring others. Before I received that I had intended to begin Spirit.—Dissolve one part of ammonia alum and two with the vomit. I received letters from Dr. Gervis and parts of sulphate of iron in 100 parts. Well wash the Mr. Caunter, clerk to the magistrates, dated July 18, in casks with this solution boiling hot, and allow them to which the former said he beliered the parties had suf- stand for 24 hours. Then rinse out the casks well, dry fered from some vegetable narcotic poison, such as atro- them, and finally give them a washing with a thin solupine or morphine. Witness then stated in great detail tion of silicate of soda.--Chem. Cent. Blatt., No. 25, p. 400. the course he pursued in his analysis of the matter which he had obtained by introducing the leg of the rabbit tion is recommended for venereal warts :-Bichloride of

Mercurialised Collodion.— The following applicainto dilute hydrochloric acid, and allowing it to soak therein, in order that any narcotic poison in the rabbit bichloride, in fine powder, is shaken up with the collodion,

mercury, 25 centigrammes ; collodion, 52 grammes. The might be dissolved out. The tests he had used, he said, and the mixture is applied with a camel's hair brush. One he had applied also to a solution of atropine which he himself made, and with precisely similar results. Mr.

or two applications will effect a complete cure. Herapath continued-I have no doubt whatever that there was atropine in the contents of the pie. I have ANSWERS TO CORRESPONDENTS. also examined the vomit, and though the indications were not so good, I have no moral doubt there was atropine

In publishing letters from our Correspondents we do not thereby there. There was none in the flour ; but I obtained some adopt the views of the writers. Our intention to give both sides of a from the scrapings of the surface of the leg of the rabbit. I question will frequently oblige us to publish opinions with which we If a rabbit had died from taking atropine I should not expect to find the poison in the surface of the leg, but All Editorial Communications are to be addressed to the Editor, in the liver and stomach. In the present case I should and Advertisements and Business Communications to the Publisher, at expect to find it in the brain and the sheath of the spinal letters for the Editor must be so marked.

the Office, 1, Wine Office Court, Fleet Street, London, E.C. Private Cross-examined : If the rabbit had eaten of belladonna I should have expected to find the poison in Vol. XI. of the CHEMICAL News, containing a copious Index, is now the liver and the brain. I have found both metallic and ready, price 118. od., by post, us. 6d., handsomely bound in cloth, vegetable poisons in the livers of animals. All parts of gold-lettered. The cases for binding may be obtained at our Ofice, the belladonna plant, I believe, are poisonous. I have price 18.

od. Subscribers may have their copies bound for 28. 6a. il

Vols. I. heard of dogs eating grass, but never belladonna. I have and II. are out of print. All the others are kept in stock. Vol. XII. never heard of any animals but goats eating hemlock, and commenced on July 7, 1865, and will be complete in 26 numbers. I do not know what the effect on them is. I received the matters on the Wednesday, but I did not find the atropine Greville Williams Chemical Manipulations."

IV. J. Grey.-A table for making the calculations is given in Mr. until the Sunday; I had twenty or thirty experiments to T. C. (Bury).-Sulphate of lime is generally obtained in that form go through. I had to satisfy myself that I was right, from acid solutions. and the first thing to do was to separate all foreign matters

marrow.

1. H.-Common salt is often used for tho purpose, and, we believe, from the poison. The first object of a toxicologist is to Received.-Mr. Newland, F.C.S.,--shall appear next week; D.; E.W.P.

answers.

CHEMICAL NEWS,
Aug. 18, 1865,

Reactions of Gelatine.

73

SCIENTIFIC AND ANALYTICAL

kept at 65° C. for six hours, and then allowed to stand CHEMISTRY.

for twenty-four hours. The precipitate is then collected on a filter and washed with equal parts of the molybdio

solution and water. Erperiments on the Precipitation of Phosphoric

Acid as Phosphomolybdate of Ammonia, by Dr. R.
FRESENIUS.

Reactions of Gelatine, by M. CAREY Lea, Philadelphia The author has studied the influence of rarious rcagents I have been occupied at times for some years past with. on the estimation of phosphoric acid by precipitation as the study of this very interesting substance, and propose phosphomolybdate of ammonia, and has cɔme to the fol- here to describe a new reaction which I have observed, lowing conclusions:-His experiments were made with and which constitutes, I believe, the first coloured reacthe same solution of phosphate of soda, jo c.c. of which tion described as produced between pure gelatine and a precipitated and weighed as pyrophosphate of magnesia perfectly colourless reagent. It is true that the precipigare as a mean o'0209 of phosphoric acid. The deter; fate produced in gelatine solutions by gallotannic acid is minations with the molybdenic solution were controlled much deeper in colour than the precipitant. But the by a re-determination of the phosphoric acid in the pre-straw yellow colour of gallotannic acid naturally leads cipitate as pyrophosphate of magnesia. Ten c.c. of the phosphate of soda solution precipitated the case I am about to mention, the precipitant is colour

to the expectation of coloured combinations, whereas in by the molybdenic solution gave o'0206 phosphoric acid, less, and the production of a marked colour seems to or 99 per cent. of the amount really present.

point to a more complete action than that of simple comNitric acid, even when in very large excess, the author bination. found not to interfere with the result.

When a piece of gelatine is dropped into an acid solu. Hydrochloric acid, when in large excess, partially ortion of pernitrate of mercury, it gradually assumes a even completely hinders the precipitation. When the strong red colouration, and after a time dissolves in it amount of the acid is as low as 3*3 per cent of the completely, at ordinary temperatures, to a fine red soluliquid, the result comes near the truth, but is always tion. This solution deepens a little if boiled for some too low.

minutes. The simultaneous presence of much nitric and hydrochloric acid completely prevents the precipitation.

By chlorate of potash the hot solution is quickly de

colourised, and passes to a pale dirty yellow. Sulphuric acid, perchloride of iron, and chloride of

This red colouration scems to require a certain amount aluminium, have but little influence on the amount of of time for its production, which cannot be replaced by precipitate. Thus the io c.c. of phosphate of soda heat. If a piece of gelatine be immersed in the solution solution, as above, gave, in the presence of sulphuric of protonitrato and boiled for some minutes it is disacid, o`0208 of phosphoric acid, and in a second experi. solved, but the solution thus obtained is not red, but ment o'0205. With perchloride of iron the same amount

yellowish. of phosphate of soda solution gave 0'0207 phosphoric acid. The pyrophosphate of magnesia solution obtained is not more delicate. It is only striking when tolerably

It is to be regretted that the reaction here described from this precipitate showed a trace of iron with sulpho- strong solutions of gelatine are employed. When the cyanide of potassium.

solution is very weak, as, for example, if the gelatine In the presence of a considerable proportion of sal. constitutes only one-half of 1 per cent. of the mixed ammoniac the amount of precipitate was always a little liquids, the limit of the delicacy of the test is reached. too low; as was the case when the solution was much Such a solution by standing twenty-four hours exhibits diluted.

a light but distinct pink colour. Although this delicacy The author made another series of experiments. is not what may be desired, still colloid organic subA solution in which the amounts of iron and aluminium stances are so comparatively difficult of qualitative degreatly exceeded the proportion of phosphoric acid, as tection as a general thing, that the method is not without when the acid is estimated in a hydrochloric extract of a value, soil. He prepared a solution that contained in a litre 20 grammes of iron, as chloride, 2 grammes of alu- A neutral meta-gelatine was prepared in the folləwing

The experiment was next extended to meta-gelatine. minium, as chloride, and o'or gramme of phosphoric acid. By the direct precipitation of 100 c.c. of this solution with the molybdenic solution, 0.00991 of phos

Gelatine was set to swell in cold saturated solution of phoric acid was obtained. 100 c.c. of the same solution oxalic acid, and then a moderate heat was applied for a evaporated to dryness on a water-bath, and the residue sufficiently long time for the mass to remain quite fluid dissolved in the smallest amount of nitric acid, also gave bonate of lime until the whole of the oxalic acid was got

when cold. It was then agitated with precipitated car0.00991 of phosphoric acid. the residue dissolved in the least possible amount of rid of. Meta-gelatine prepared in this way was kept hydrochloric acid, gave only o‘00972 phosphoric acid.

for months in a corked phial, in a warm room, without The above results will serve to guide analysts in the showing any disposition to putrefy. It was almost as use of the process mentioned for determining phosphoric the taste.

fluid as water ; perfectly neutral, and almost insipid to acid. We ought perhaps to state that the author prepares liis molybdic solution by dissolving one part of

With this meta-gelatine, the red colouration was promolybdic acid in four parts of ammonia, sp. gr. o.96, duced even more decidedly than with ordinary gelatine. and adding to the solution fifteen parts of pure nitric The addition of the acid solution of pernitrate of mercury acid, sp. gr. 1'2. In making the determinations, thc produced at first a whitish flocculent precipitate, which, phosphoric and molybdic solutions are mixed hot, and are by standing, acquired a strong red colour, as did the

supernatant liquid.- American Journal of Science and Abstract from Zeitschrift für Analyt. Chem., No. 4, 1864, p. 447. Arts, vol, xi., No. 118, VOL. XII. No. 298.-Avqust 18, 1865.

manner :

CHEMICAL News,

74

Supposed Nature of Air prior to the Discovery of Oxygen. (Carcas,

On the Supposed Nature of Air prior to the Discorery immediately rose to the piston.

observed not to follow it, but when air was admitted it of Oxygen, by George F. RODWELL, F.C.S.

Experiment 35. A cupping glass was attached to the (Continued from page 61.)

palm of a person's hand by the usual method; the hand In the 17th experiment Boyle describes the way he was then made to act as a cover to a small receiver ; on adopted to determine the degree of exhaustion of a re-exhausting, the cupping glass fell down. ceiver. In his first attempts he placed a securely closed

Experiment 40. Some small feathers were detached bladder containing a small quantity of air in the receiver from the top of a tall receiver ; before exhaustion they to be exhausted, and considered the exhaustion good fell slowly, and wavered in their course; after exhaustwhen the bladder was fully inflated. He afterwards ing the receiver, they fell “ like a dead weight.” ineasured the exhaustion by a small U tube, closed at

Experiment 43. Sugar was submitted to friction in one end, which was filled with mercury, and a small an exhausted receiver, and was found to emit light as bubble of air then passed into the closed end. The tube readily as in air. was placed in the ressel to be exhausted, and the rare. Experiment 45. In order to ascertain whether heat faction judged of by the expansion of the bubble of air. could be produced by friction in an exhausted receiver,

Experiment 18. * About an easie way to make the a concare piece of brass was fixed to the air pump plate, pressure of the air sensible to the touch of those who a conves piece of the same metal was connected with a doubt it.” In order to effect this, Boyle constructed a rod which passed air-tight through the cover of the small brass receiver of the form of a truncated cone, open receiver, and could be turned by a handle, when the two above and below; the upper orifice was if inch diameter, surfaces were rubbed together in vacuo, a considerable and the lower, which stood on the air pump plate, 24 amount of heat was found to be produced. inches. “ The person,” he writes,“ that would not believe

Experiment 46. Quicklime was slaked in an exhausted the pressure of the air to be near so considerable as was receiver, and heat was found to be produced as readily represented was bidden to lay the palm of his hand

upon as when it was slaked in air. the upper orifice, and being ordered to lean a little upon

With this experiment we conclude our notice of it, that so the lower part of his hand might prove a close Boyle's second pneumatical treatise; there are altogether cover to the receiver, one exsuction of the air was made fifty experiments, of these we have noticed the inost by help of the pump; and then upon the withdrawing important, omitting those which are only slightly of the greatest part of the pressure of the internal air, modified forms of experiments described in the foriner that before counterbalanced that of the external, the treatise. hand being left alone to support the weight of the ambient air, would be pressed in wards so forcibly that, PHARMACY, TOXICOLOGY,&c. though the stronger sort of men were able (though not without much adoe) to take off their hands, yet the On Tobacco, by FERDINAND F. MAYER, of New York. weaker sort of tryers could not do it (especially it by a NUMEROUS as have been the essays published both on second suck the little receiver were better exhausted), the chemical and the therapeutical relations of Nicotiana but were fnin to stay for the return of the air into the Tabacum and its narcotic principle, they refer for the rcceiver to assist them.”

greater part to the leaf of the usual brown colour and Experiment 31. A magnet was loaded with the utmost well-known irritating ammoniacal odour, which is the weight it could carry. It was then introduced into a form officinal in all Pharmacopæias ; for, though unireceiver. On exhausting, the weight still continued to versally cultivated, the plant is never prepared specially be supported.

for application in incdicine like other narcotics, partly Experiment 32. A small brass syringe was taken, and because of the commercial article being still more readily the piston forced to the bottom of it, the orifice of the obtainable, but in yet greater measure, because the fresh syring was then closed securely; when the piston was and the dried green leares have very generally been conraised, great resistance was felt, and on releasing it the sidered, if not devoid, to be at least of very feeble pressure of the air of course caused it to return to its developed medicinal virtues. Only those of another former position. It was now placed in a receirer, and species, N. rustica, are occasionally used fresh as an exthe piston handle placed in cominunication with the ternal application, and are, or weic formerly officinal in stopper of the receiver by a piece of string, so that by some European Pharmacopæias. turning the stopper the string was shortened, and the There is so striking a difference in many of the outer piston consequently raised; when the receiver was properties of the officinal plant, in the green and the exhausted, the piston was casily raised to the top of the cured condition, as to offer in itself some grounds, for syringe, when it was kept in that position, and air what was formerly universally and is even now very admitted, the piston was immediately impelled to the generally believed, that the volatile alkaloid on which bottom of the springe, and the string which held it was the activity of brown tobacco is supposed to depend was broken. The above experiment was varied by suspending not present as such in the living plant, but that it is a a closed syringe in tlie air pump receiver by its piston posthumous product formed entirely. or partly during rod, and attaching a weight to the barrel not sufficient that incomplete fermentation which it undergoes in the to draw it down-in other words, not sufficient to over- hands of thie cultivator, the “ bulking" of tobacco. For, come the pressure of the air on the area of the piston. the fresh p!ant possesses none of the peculiar heary On exhausting, the barrel immediately descended, and odour of the other narcotics. Nor is the dried leaf much when air was admitted it rose to its former position, more pungent than a common herb. Its infusion, like dragging up the weight with it.

the fresh juice, has an acid reaction, and contains no Experiment 34. A syringe was placed in a receiver in ammonia. Its colour is pale green, with here and there such a manner that its piston could be raised when the some brownish patches ; but the taste is decidedly acrid. l'eceiver was exhausted; a glass tube was fitted to its and certainly only differs from that of the commercial nozzle, and its lower orifice caused to dip into mercury; article by the absence of free ammonia. It also contains on exhausting, and raising the piston, the mercury was a large proportion of nicotina in combination.

CAENCAL News,
Aug. 18, 1865.

On Tobacco.

75

This had been pointed out as early as 1809 by Vau- the matter, especially in regard to the seed, be again quelin, in the report made by him with Robiquet and made the subject of research, and since this investigaU.S. Consul Warden. It was again shown to be present tion has been undertaken by me, fresh interest has been by Posselt and Reimann, in 1831, in plants of several imparted to it by the publication of a paper on the same species grown near Heidelberg, and again in 1836 by subject in the Vierteljahresschrift für Pharmacie of Henry and Boutron-Charlard; and in 1831 A. Buchner, April last. The author of this essay found a volatile sen., prepared some nicotina from the seeds. Lastly, principle, which on the strength of its odour he assumes our excellent Proctor, in 1858, prored without doubt to be trimethylina (pseudo-propylamin,) said to have orithe presence of the alkaloid at least in the fresh ginated from a fermentable substance contained in the leares; and the authority on whose credit the origin sced, and he believes that Buchner mistook a mixture of by fermentation had been maintained, corrected ihe ammonia and trimethylina for nicotina. siatement made there as early as 1844, upon the In order to avoid, if possible, errors arising from ie. occasion of a paper on tobacco smoke by A. Melsens, in liance upon such deceptive characteristics as odour, and a note to which (Annalen der Chemie und Pharmacie, because in the examination of the plant at least two bases rol. 49, p. 359) Liebig mentions that “at the Giessen are met with possessing a pungent and somewhat similar Laboratory not inconsiderable quantities of the alkaloid odour, I have made use, besides the usual distinction had been obtained from the fresh plant."

resting on the percentages of platinum in the double With such evidence the presence of nicotina in the salts of the volatile bases, of the following tabic founded plant, through its various stages, may be accepted as on previous and new observations of Nessler, Winckler, satisfactorily proved. Yet Mr. Proctor suggested that Proctor, myself, and others :-

Principal Reactions of the Medicinal Volatile Bases.

(w. watery solution; 4. = salts, or acid solutions )

cess.

[ocr errors]

Reagents added to
Ammonia. Trimethylina.

Anilipa.
Nicotina.

Covia.

Lobelina re, and 8. Orange. Brown so uticn; ro. and 8. Brownish w.and 8. Pale brown-19. and s. Brownish lorline in lodide af! ". Decolorised.

s. No cbange. Potassium

coloured precipi-l afterwards a pre

red precipitate. ish - red precipi. red precipitate. tato. | cipitate, or none.

tato. 2. No precipitate. Neutral and alka- No precipitate.

Whitish precipi-White precipitate, White precipitate, of 8. Precipitate

line Tannic Acid

solutions ;

tate, soluble in soluble in tannic soluble in tannin tannin if concen- white, curdy pre

acids.

and other acids. and ammonia trated.

cipitate.

precipi. No precipitate. 10. White precipi. 2. White procipi- 20. No precipitate. Chloride of Mercury

... White precipi- 2. White
tate.
tate.

tate.

tate. 4. No precipitate ; 8. A loose mass of ro. Solution ; white w. and e. Yollowish u. and s. Same as u. and 8. Pale yellow with caustic Ko pale yellow crys. precipitato, solu: precipitate, some

nicotiua.

precipitate, little orange to brown tal-, very soluble ble in excess and what' soluble in

solublu in excess precipitate. in excess of iodide in KI, reproduced excessof re-agent,

of re-agent or of 8. White to yellow of potassium, by ko, but re- and readily solu

caustic ko. lodohydrargyrate of precipitato, solu- and caustic Ko; dissolved by ex- ble in caustic KO. Polassium

ble in excess. decomposed by cess of the sime.

shaking with

water.
w. Precipitatewhich

re-dissolves in exAcetate of Leal* 2. Brownish-black. 2. Greyish, soluble No precipitate. 10. At first no pre-ro. White precipi- 2. White precipiiu nitric acid.

cipitate, but

tate, turning tate, soluble in

brownish · black brownish, soluble ammonia and Nitrate of Silver

one (in heating. in ammonia, at nitric acid.

first also in nitric

acid. 20. Reddish - yellow 10. Greyish - yellow, 20. Nu precipitate. 2. Yellowish,curdy, w. Whitish, insolu-20. Palo yellow, inChloride of Gold

insolublo in by.
insoluble in Hci.' ble in HCI.

soluble in HĆI. drochloric acid Chlorideos Platinumut Density and SoluVery soluble; nises Very soluble; mixes. Scarcely soluble ; Little soluble ; Little soluble ; Little soluble ; bility with water.

floats.
sinks.
floats.

floats. • In the watery solution, except of anilina, å white precipitate. + Distinct precipitate only from nicotina, which dissolves on heating.

Course of Proceeding.-The volatile alkaline sub- 2. The precipitate is scarcely soluble in excess of merstance having been obtained in form of a concentrated cury, but readily, while fresh, in caustic potassa : nicotina, solution in water, and in part as solution in hydrochloric conia. Apply the specific tests. acid, a drop of a solution of iodide of potassium saturated 3. The precipitate is scarcely soluble in either: lobewith iodide of mercury is added to part of the acidulated lina. solution. Either,

I. It produces no precipitate.-Absence of trimethy- Armonia.-Its reactions, as, for instance, that with cobalt, aro lina, nicotina, lobelina, conia. To a portion of the un- rendered indistinct by the presence of carbonic acid. changed solution add caustic potassa in slight excess, never free from anmonia, which is readily ascertained in an acid solu

Commercial trimethylina (the medicinal propylamin) is probably which causes a precipitate. It is

tion by the test with iodohydr.rgyrate and caustic potassil. It should Whitish and pulverulent: anilina.

be perfectly colourless and clear, of a faint odour of ergot rather than

of herring, and must burn like alcohol. Reddish to brown and flocculent: ammonia.

Conia, when quite pure, is colourless, and a peci:liarly swoet, II. A precipitate is produced. -Add excess of the solu respects ; has an herbaccous odour, recalling that of Prussie acid.

Lobelina resembles it in aany

but rancid or somewhat musty odour. tion of mercury.

The alkaloids tested wera freshly prepared for the experimenis by 1. The precipitate re-dissolves very readily : triunethy- the method described further on for nicotina. lina.

(To be continued.)

{precipitate.

76

College of Physicians.

CHEMICAL News,

Aug. 18, 1865.

—that acetic acid C,H,O.,, for instance, was associated PROCEEDINGS OF SOCIETIES. with the less oxidised bodies, olefiant gas C,H,, alcohol

C,H,O, and aldehyde C,H,O, as well as with the more COLLEGE OF PHYSICIANS.

highly oxidised glycolic and oxalic acids, C,H,O, and

C,H,O, respectively- to such an extent, indeed, they might Wednesday, May 3, 1865.

all be regarded as varieties of one and the same primitive On Animal Chemistry.A course of Six Lectures by molecule. I further went on to say that the complex WILLIAM ODLING, M.B., F.R.S., F.R.C.P.

tissue products of the animal and vegetable kingdoms

were built up of the residues of these fatty and aromatic LECTURE 3:

acids, and of their respective congeners; so that upon Recapitulation-Statical and dynamical aspects of organic breaking up such tissue products into their constituent

chemistry-Destruction and construction of constituent molecules, we were, in the great majority of instances, aplone molecules-- Tendency of oxidation to produce mole- able, even at the present time, to refer the constituent cules with fewer and fewer carbon and hydrogen atoms- molecules to their appropriate positions in certain defiFinal production of carbonic anhydride Con, and rater nite series and groups, and had every reason to believe 11,0-Destructive or analytic phase of organic chemistry that with increasing knowledge we should be able to make -Natural synthesis of organic compounds attended by the assignment in every instance. Again, in my first deoxidation Liberation of oxygen by growing vegetables lecture, I pointed out to you that organic chemistry had a - Tendency of deoxidation to combine separate carbon and statical aspect which related to the composition of bodies, hydrogen atoms into complex molecules-Vegetable tissue and a dynamical aspect which related to their changes of and secretion formed by deoxidation of carbonic anhydride composition. and water - Imperfect knowledge of intermediate products

Now, in all that I have hitherto observed, I have had - Formation of nitrogenised tissues -- Ammonia in its regard principally to the statical aspect of the question. relations to plant-life-Correlations of ammonia, nitrous I have, indeed, glanced at the mutual metamorphosis by acid, and nitrogen-Deoxidation of nitrous acid by plants oxidation and deoxidation of compounds belonging to the - Manurial equivalency of nitrous acid and ammonia- same natural group, and havereferred more fully to the comExistence of nitrogen in natural organic products as a bination of different residues with one another in forming residue of ammonia-- Artificial synthesis of organic bodies complex tissue products, and to the separation of the comCombination of constituent molecules with one another pleted residues from one another in the breaking up of - Elementary formation of constituent molecules-His- these products; but I have not considered the mode in torical remarks on organic synthesis - Alleged incompetency which the primary constituent molecules are themselves of chemical, and necessity for vital action - Artificial pro- produced, or yet the mode in which, when once production of all organic compounds by purely chemical duced, it is possible for us to destroy them, and to these means— Kolbe's indirect formation of acetic acid from points I will now direct your attention. carbon, hydrogen, and oxygen, in 1845 — Subsequent

If we treat the more complex members of our series advances by Berthelot and others-Oxidation of hydrogen of fatty acids, for instance, with powerful oxydising into water, and of carbon into carbonic anhydride - Evolu- agents, we obtain bodies in which the number of the contion of light and heat-Deoxidation of water and carbonic stituent atoms of carbon and hydrogen becomes proanhydride into hydrogen and carbonSimilar separations gressively less and less, until we arrive at bodies containing of carbon and hydrogen effected by living plant and by only two, and finally at bodies containing only one atom of artificial processes- Comparison of deoxidising vegetal and carbon. In some cases these successive oxidation products oxidising animal functions-Nature of forces concerned in are found to contain the same number of atoms of oxygen as respective actions.

the bodies from which they were produced, though in the I OBSERVED in my last lecture that chemists were ac

majority of instances they contain a greater number, and,

But quainted with a great number of monobasic organic acids, consequently belong to more oxygenised series. containing two atoms of oxygen in their respective mole- whether they contain the same or a greater number of cules, and that these acids were capable

of being arranged oxygen atoms, we find that the number of atoms of carbon in two principal classes, known as the aromatic class and and hydrogen becomes gradually less and less, or that the the fatty class, as exemplified in the accompanying lists :

molecules pertain to simpler and simpler groupings. For

example, the following intermediate compounds, among Fatty Acids.

Aromatic Acids.

many others, have been successively obtained by oxidising Formic Сн, 0,

Collic C. H, 02 stearic acid Ci;H3402, with nitric acid of moderate Acetic C, H, O

Benzoic C, H, O, strength :
Propionic C, HC
Toluic

Oxidation Products.
Butyric CH
Picic

Rutic acid C H200,
Valeric C. Ho
Cuminic Clu220,

Suberic

C2H40

Enanthoic C, H40, Melissic Cz8.02

Pimelic

C,H,20 The acids of these two series presented, I told you, a

Caproic CH,02 marked parallelism in their constitution, seriation, and

Adipic

CH,00 properties; and, moreover, when submitted to the action

Butyric C, H, O, of the same chemical reagents, underwent precisely

Сн, О. similar metamorphoses. I dwelt still more upon the T'he tendency of oxidation, then, is to separate the mutual resemblance manifested by consecutive members constituent carbon and hydrogen atoms from one another of the same series, and pointed out that even the most until at last there is left only the most stable mono-carbon remote members were distinguished from one another by compound known to chemists, namely, carbonic anhygradational differences only. I observed, also that dride, or, as it is frequently called, carbonic acid. No each one of these primary monobasic acids, fatty or matter what the complexity of the original molecule, the aromatic, was associated with a or less com- chemist eventually succeeds in transforming it by oxidaplete set of congeners, which differed from it in con- tion, through a series of less and less complex molecules, stitution and properties, but correlated with into carbonic anhydride, or oxide of carbon, on the one it by the circumstance of their containing the same hand, and water, or oxide of hydrogen, on the other—the number of carbon atoms, and still more markedly by their identical bodies out of which the vegetable organism derivation from, and convertibility into it and one another directly, and the animal organism indirectly, constructs

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Succinic

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