Obrazy na stronie

College of Physicians.


{ Sept. 1, 1865. bable that certain vegetable products of deoxidised car- Now, by a variety of processes, some new, some old, bonic acid and water may have undergone a partial reoxi- it is, and for a long time past has been, possible for dation, or even several alternate reoxidations and deoxida- us to fasten on to one or other of these or allied tions, in the course of their history. Similarly in animals, alcohol bodies an additional atom of carbon, in such a although the ultimate process is one of oxidation, we way as to produce the acid corresponding to the alcohol know that some proximate principles of food experience next in the series. Thus, by means of prussic acid CHN, iin oxidation of certain of these constituents at the expense or carbonic anhydride CO2, or phosgene CoCl2, we can of the remainder, which consequently become deoxidised; convert methylic alcohol into acetic acid, vinic alcohol into and it is possible that some animal products may have propionic acid, propylic alcohol into butyric acid, and so undergone an entire deoxidation, or even several alternate on; but until very lately we could not step from acetic to deoxidations and reoxidations, before their final discharge propionic acid, or from propionic to butyric acid,—that is from the body. On all these points very much yet remains to say, we could obtain butyric acid c 6,0; from certain to be learned'; but still, the general position holds good, members of the 3-carbon group, but not from those members that vegetables effect a simultaneous deoxidation and inter- which we had ourselves produced from the z-carbon group; combination of carbon molecules, while animals conversely and, similarly, we could produce propionic acid C,H,O,, effect their simultaneous reoxidation and separation. In from certain members of the 2-carbon group, but not from many instances, also, the representatives of certain stages those members which we had ourselves produced from the of building up and breaking up, in vegetable and animal :-carbon group. The series of synthetic operations by which life respectively, are closely allied to, or even identical it would be possible to pass from any group not merely to with, one another. Oxalic acid, for instance, the simplest the next, but to the next but one, and so on ad libitum, product of vegetable synthesis, and a frequent constituent was incomplete through a want of knowledge of the of both the highest and lowest vegetable organisms, may metamorphic relation subsisting between the acid and be formed, as we have just seen, by a deoxidation of alcohol of the same group. The alcohol, and not carbonic acid. But it also occurs abundantly in animal the acid, being the plastic member of the group, we juices and secretions, not as a product of the deoxi- could convert the 3-carbon alcohol into the z-carbon dation of carbonic acid, but as the last interme acid, and the 2-carbon alcohol into the 3-carbon acid, and so diate stage in the oxidation or downward transforma on; but being unable to convert the 2-carbon acid into the tion of more complex bodies into carbonic acid ; just 2-carbon alcohol, we could not by any means pass from the as the oxalic acid of commerce is obtained from 3-carbon to the 3-carbon group. Very recently, however, sugar by a process of oxidation which, if carried too far, this difficulty has been overcome by the separate researches yields little else than carbonic acid. Benzoic acid, again, of Wurtz and Mendius, who have shown us how to transenjoys a wide distribution in the vegetable kingdom as a form any acid into its corresponding alcohol ; whereby a product of deoxidised carbonic acid, and is also a constant continuous series of synthetic processes may now be carried result of the natural and artificial oxidation of animal on as far as we please. Without entering into purely chetissues. The power, then, of producing such bodies as mical details, I may say that the process of Wurtz consists benzoic acid and oxalic acid out of more complex bodies in transforming the aldehyd of the acid into the normal such as albumen and sugar, by artificial processes of oxi- form of the alcohol ; while that of Mendius consists in dation more or less similar to the natural processes taking transforming the nitrile of the acid into the ammoniated place in the animal body, has for a long time past been in form of the alcohol, by means of nascent hydrogen, as illusthe acknowledged possession of the chemist. Now, I trated below in the case of ethylic alcohol, thus :propose to furnish you with illustrations of his inverse


Ethyl-amine. power, to which I have so often referred, of producing

CHAN + H C,H,N or C, H.HN both animal and vegetable compounds by deoxidising, or synthetic, or vegetative processes--that is to say, of form


Ethyl-bydrate. ing organic compounds without having recourse to living C,1,0 + H, C,H,O or C,H,.HO organisins or vital forces. I will first give you an account of the general pro

Ethyl-chloride. cesses employed for passing from a more simple to a

C,H,Cl or C,H.CI. more complex group, and then of the particular processes The amine is readily convertible into the hydrate, and by which certain individual substances have been pro, the hydrate into the chloride, bromide, or iodide ; duced, interspersing some remarks upon the nature and which last bodies, or their metal derivatives such, relationship of the substances themselves... At starting, for example, as sodium-ethylate CH.NaO, and sodiumlet me recall to your recollection the associated series of ethyl c H Na — are the forms of alcohol most usually homologous fatty acids and alcohols, as written up on the employed in actual synthetic processes. Prior, then, table before you:

to this discovery by Wurtz and Mendius, of means Acids.

for passing from the acid to its alcohol by hydroCH, O Methylic.

CH, 0, Formic. C,HO Ethylic.

C,H, 0, Acetic.

genation, although many important syntheses had

been effected, there had been no consecutive series of CH, O Propylic.

CH, 0, Propionic.

syntheses. The previously known processes would allow CHO Butylic.

CH, 0, Butyric.

us to pass from certain mobile members of one group to C,H,20 Amylic.


certain immobile members of the next, but would carry CHO Caprylic.

CH 20, Caproic.

us no further. Nowadays, however, by transforming CH0 Anthylic.

C,H140, Enanthic.

the immobile acid into the mobile alcohol, we can CHO Octylic.

C2H60, Thetic.

proceed continuously through an apparently unlimited Each of these alcohols and acids is, moreover, associated series of synthetic operations. Letting co stand for the with a set of bodies having to it the same relations that transferable part of carbonic anhydride CO2, phosgene ammonia, hydrochloric acid, and hydrogen have to water, COCly, and hydrated prussic acid CHN.H,0, we should as explained in my first lecture, and as shown below in the have the following series of operations leading to the procase of ordinary alcohol :

duction of fatty acids and alcohols of any degree of comTypes. Ethyl-derivatives.

plexity, each of them capable of metamorphosis into (Н.

Hydride of ethyl or ethene. scores of allied compounds, which again are capable of (H.C CH, C Chloride of ethyl, or chlorethine. entering into combination with one another, as explained

11.'10. C,HZ.HO Hydrate of ethyl, or alcohol. in my second lecture, to form still more numerous and H.H,N C,H,HAN Amide of ethyl, or ethylamine.'complicated bodies.


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kingdom it has been occasionally recognised in human 1-Carbon alcohol C HO + CO = C,H,O,

blood, urine, perspiration, and in the fluids of the spleen Acetic.

Ethylic. and muscles. It also exists largely in the juice of red ants 2-Carbon acid C,H,O, + H H2O + C27,0. from which it may be obtained by simple distillation, and Ethylic.

Propionic. -Carbon alcohol C28.0 + CO

in the corrosive fluid of certain caterpillars, &c. Now, C2#160g.

by combining formic acid with ammonia, we obtain forPropionic.

Propylic. miate of ammonia, which yields by dehydration that im3-Carbon acid C,8,0+ H H2O + C8,0. Propylic.


portant organic compound met with in cherry-laurel water, 3-Carbon alcohol C,0 + CO = C,H,O,

bitter almond emulsion, &c., and known as prussic acid or Butyric.

cyanide of hydrogen, thus :C,HO, &c., &c.

Formic acid. Ammonia. 4-Carbon acid

Water. Prussic acid. CHO,

HEN 2,0 Starting from the 1-carbon or methylic alcohol, we can Moreover, this acid or


a corresponding cyanide may convert it into the 2-carbon or acetic acid by wellknown processes.

But in order to proceed from the nowadays be procured, not only from formic acid, but 2-carbon aoid, we must first transform it into the z-carbon by the direct combination of carbon, nitrogen, and a alcohol—the alcohol, in some or other of its forms, being CKN, for instance-we obtain cyanate of potassium

metal. Again, by oxidising a cyanide-that of potassium the synthetic starting point, so to speak—and this we have very recently learned to do. Then, by affixing deoxidised of ammonia, which changes spontaneously into urea, thus :

CKNO, convertible by double decomposition into cyanate carbonic anhydride on to the 2-carbon alcohol, we con

Ammon. cyanate. vert it into the 3-carbon or propionic acid. Then by acting upon propionic acid by deoxidised water, we trans

CHNO.HN CH,NO, form it into propylic alcohol, upon which we again affix

This is the celebrated reaction by which urea was first prodeoxidised carbonic anhydride to convert it into the duced artificially by, Wöhler in 1828 ; but at that time the 4-carbon or butyric acid, and so on continuously, by a cyanogen of the cyanide of potassium employed was series of deoxidising actions with carbonic oxide and known only as a product of organic origin. You observe hydrogen alternately.

that by oxidising formic acid we obtain carbonic acid ; and Now let us proceed to notice briefly, in the order of their by oxidising the mon-ammoniated form of formic acidcomplexity, some of the more interesting organic or carbon namely, prussic acid-in presence of more ammonia, we compounds which have been produced artificially by obtain the di-ammoniated form of carbonic acid-namely, elementary synthesis. Among mono-carbon compounds urea, which has since been produced by several other we have first carbonic acid CH,Oz, alike the most im


processes. portant product of animal oxidation and subject of veger the methyl sub-group, and are, principally

The still less oxidised monocarbon compounds belong to table deoxidation. Associated with carbonic acid or hydrate, we have carbonic amide or urea CH.N,0, a body

Methyl compounds. standing towards carbonic acid in the same relation that

or CH2.H Methyl hydride or marsh gas. ammonia stands to water, and convertible into the acid by CH2Cl or CHz.cl Methyl-chloride. an exchange of certain elements of ammonia for the corre

CH,O or CHZ.HO Methyl-hydrate or wood spirit. sponding elements of water, thus :

CH N or CH,H. N Methyl-amine. Urea.

Ammonia. Carbonic acid. (CO)_HN+ (H)9,0% = (Hạ)HN, + (CO)?H,O.

These four bodies the methyl varieties of hydrogen, Carbonic acid is also met with in its dehydrated form as

hydrochloric acid, water, and ammonia-are mutually concarbonic anhydride CO2, and as the sulphur derivative of to its occurrence as the chief constituent of coal gas, as

vertible by a variety of processes. Marsh gas, in addition that body or carbonic sulphanhydride CS. These compounds are obtainable by burning charcoal in oxygen and the fire damp of coal mines, and as the gas of stagnant sulphur respectively, the last of them, under the name of ponds or marshes, has recently been recognised by Petten

kofer as a normal ingredient of expired air, Wood spirit, disulphide of carbon, being now produced on an enormous scale for certain manufacturing uses. The anhydride is again, is not only a product of destructive distillation, but readily procurable from the acid by dehydration, thus :- oil of wintergreen, thus :

occurs in nature as a constituent residue of the essential Carbonic acid. Water. Carbonic anbyd. CH,02

Salicic acid.

Wood spirit.

Wintergreen oil.

Cg8,0, + H,O C4H6O3 + CHÁO and reconvertible into the acid or its salts by actual or

Among other well known methyl compounds may be potential rehydration, thus :

mentioned sarcosine, kreatine, caffeine or theine, theobroCarb. Potash.


Lime. Chalk. anhyd.


mine, coniine, narcotine, &c., &c. The production of CỐ, + KHO=CKHO, and CỎ,+ CaO = CCа"Oz.

methylic from carbonic or formic compounds may be effected The deoxidised forms of carbonic acid and anhydride, or

in a variety of ways. Thus prussic acid, by hydrogenation, formic acid CH 02, and carbonic oxide CO, respectively,

yields methylamine:are readily procurable therefrom by processes of reduction,

Prussic acid. Hydrogen. Methylamine.

CHN and are correlated with each other in a similar manner,

CH, thus :

Formiate of barium is decomposed by heat with proCarb.



duction of marsh gas; thus :-


oxide. Barium formiato. Barium carb. Carb. anhyd. Marsh gas. co + KHO = CKHO, and CHÀOA – HÀO CO.

CH ,
2CBa", + CO,

+ CHA The production of formic acid or formiates by the reduc

CH O, tion of carbonic acid with sodium (Kolbe), and by the Marsh gas also results from passing a mixture of carcombination of potash with carbonic oxide (Berthelot), bonic sulphanhydride and sulphuretted hydrogen over being among the early examples of the formation of organic metallic copper heated to redness, thus :from inorganic compounds, excited on their first announce- Carb. sulph. Hyd, sulph. Copper. Cupr. sulph.

Marsh gas. ment a large amount of chemical interest. Altogether, CS

2 H,8 Cug 4Cu_s + CH, formic acid enjoys a very extensive natural distribution. Perhaps a still more interesting mode of obtaining In the vegetable kingdom it occurs in the juice of the methyl compounds consists in submitting disulphide of stinging nettle, in decaying pine needles, and as a product carbon to prolonged treatment with chlorine gas, whereby of the spontaneous oxidation of turpentine. In the animal' it is converted into perchloride of carbon, which by the



Potas. bicarb.






Sept. 1, 1866.


College of Physicians.


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continuous action of nascent hydrogen yields the follow- inferior chloride of copper, whereby it is retained in the ing series of compounds :-

form of cuprous acetylide C,HCu. This compound is Marsh-gas Derivatives.

thrown down as an abundant bright red precipitate, and, C Cl. Perchloride of carbon.

by treatment with warm hydrochloric acid, is decomCH Cl, Chloroform.

posed with liberation of acetylene gas, thus :CH,Cl, Dichloromethene.

Cupr-Acetylide. Chlorhyd. acid. Cuprous chlor. Acetylene. CH CI Chloride of methyl.



C,H, сн. , Methene, or marsh-gas. Thus among monocarbon compounds of purely artificial

Acetylene is characterised by the extreme luminosity with production we have the following interesting bodies, of which it burns. You observe the great opacity and whitewhich all save the last occur naturally in the vegetable or

ness of its flame, and the large amount of light afforded by animal kingdom--namely, urea, formic acid, prussic acid, with the flame of ordinary coal gas, of which, indeed, acety

it in proportion to its bulk, when compared, for instance, methylamine, marsh gas, and chloroform.

The principal members of the dicarbon group, namely, lene is a constituent, though only to a small extent. Upon alcohol and acetic acid, together with their respective hydrogenising his cuprous acetylide by means of zinc and congeners, are procurable from monocarbon compounds by ammonia, Berthelot produced olefiant gas, from which, by a variety of processes. Thus, according to some observa- indirect hydration with sulphuric acid, he afterwards

Now, tions of my own, on submitting a mixture of marsh-gas obtained alcohol, as I have already described. and carbonic oxide to a full red heat, acetylene or klumene among other animal products, alcohol occurs is produced thus,

residue of tyrosine, a compound to which I shall refer Marsh-gas. Carb. oxide.

more particularly in my next lecture ; also in triethylamine,

a constituent of the brine in which herrings and other fish сн. CO H,

C2H2; and this klumene, when acted upon by nascent hydrogen, taurine, which is producible in the following manner :

have been pickled ; and, as I have before observed, in yields olefiant gas, or ethylene, thus :

Under certain circumstances, the residues of alcohol and Hydrogen. Ethylene.

sulphuric acid combine with one another to form isethionic C,H, H, C2H4

acid, easily convertible into chlorethyl sulphurous acid Now, olefiant gas, as pointed out by Faraday and cu cisog, by means of pentachloride of phosphorus. Hennell nearly fifty years ago, and as rediscovered and This chloride is retransformable into its hydrate or established beyond question by Berthelot within the last isethionic acid C,H(HO)SO3, by the action of water, few years, is absorbed by oil of vitriol, and upon distilling while both the chloride and the hydrate are transformable the diluted acid, is liberated therefrom in the form of into the amide or taurine C,H,(H2N)SO3,* by means of alcohol or spirit of wine, thus :

of ammonia, according to the following reactions, the first Ethylene. Alcohol.

of them due to Kolbe, the second, which is earliest in point C,H, + H,O C,H,O.

of time, to Strecker :This production of alcohol from olefiant gas, or ethy- Chlorido & Hydrate.

Taurine or Amide. Jene, an important constituent of ordinary coal gas, is un- C,H,CISO, H(H,N) нсі + C,H,(H,N)SO, doubtedly, in many points of view, a result of very great c H (HO)ŠO3 + HHN) = 1,0 +

= H,0 + Cu(HNSO interest, but as a step in organic synthesis I think its importance has been somewhat over-estimated-alcohol

Now, alcohol is procurable from acetic acid by the hydroand olefiant gas being closely allied members of the same genising processes of Wurtz and Mendius, already decarbon group. However, Berthelot's discovery of a process

scribed; while acetic acid is reprocurable from alcohol by for obtaining alcohol by purely inorganic means naturally oxidation, as in the ordinary manufacture of vinegar. Moreachieved considerable notoriety, and gave a great impetus from methyl alcohol cu o, by fixation of carbonic oxide

acetic acid C,H,02, may be obtained synthetically to the general prosecution of synthetic methods. observe that the alcohol is produced from olefiant gas, co, according to the previously mentioned general which is itself produced from acetylene or klumene, which methods; and also from disulphide of carbon by Kolbe's is itself produced from monocarbon compounds of strictly historic process, referred to in my last lecture. The mineral origin. But a still more interesting way of obtain successive stages of this, the earliest unimpeachable proing acetylene has also been rediscovered and established

cess for obtaining an organic compound by strictly by Berthelot, namely, the combustion, so to speak, of mineral means, are as follows:-Disulphide of carbon carbon in hydrogen gas. When charcoal is burnt in CS,, is first obtained by the combustion of charcoal in oxygen, the heat evolved by the initial combination is more

sulphur vapour. When this compound is acted upon by than sufficient to maintain the combustion, and accord-chlorine at a high temperature, it is converted into chloride ingly the piece of charcoal when once ignited continues of sulphur and chloride of carbon CCR: Now, by transto burn. But in the combustion of charcoal in hydrogen, mission through red-hot tubes, this last compound is if it may so be called, the piece of charcoal has to be transformed, with evolution of chlorine, into the so-called maintained throughout in an intense state of ignition by sesquichloride of carbon, 2CC = Cl2 + C,Cle, and evenmeans of the electric arc. When, for instance, the char tually into the so-called bichloride of carbon or tetracoal terminals of a moderately powerful battery, enclosed chlorethylene, C.Clo= Cl2 + Cycle. In the course of his in a globe through which a current of dry hydrogen is exanıination of this tetrachlorethylene, Kolbe observed that passing, are approximated to each other so as to become by exposure to chlorine in presence of water, it was decomignited, as in the ordinary electric lamp, the hydrogen posed into a mixture of trichloracetic and hydrochloric and ignited carbon combine with one another to form acid, thus : hydride of carbon or acetylene, much in the same way Chlor-ethylene. Water. Chlorine, Chlorhyd. acid. Chlor-acet acid. that oxygen and ignited carbon combine with one another C,Cl + 2H2O + Cl2 3HCI C,HCl0, to forin oxide of carbon or carbanhydride. But oxidation tends to the separation, hydrogenation to the Then by subjecting this trichlor-acetic acid to the action conjunction of carbon atoms; and accordingly, by the of nascent hydrogen, he successively converted it into combustion of charcoal in oxygen we obtain only the dichlor-acetic acid C, H,C1,02, monochlor-acetic acid mono-carbon compound CO2, whereas by its combustion C,H,C10,, and finally into normal acetic acid C,H,O,, in hydrogen we obtain the dicarbon compound C,H2, which is separated from the excess of hydrogen by trans

* These formulæ are not meant to express the assumed internal mission through an ammoniacal solution of the white or

molecular arrangement of the three bodies, but only their positively ascertained mutual relationship.


Sept. 1, 1865.


College of Physicians.


which thus resulted from the series of transformations in- with as a glyceride in goat's butter, while amido-caproic dicated in the table before you :

acid or leucine is an occasional constituent of human Acetic Acid Synthesis.

urine, and a constant product of the metamorphosis of CS Carbon disulphide.

glandular tissue. Grape sugar C6H12O6, mannite C6H1406 C cl, Carbon tetrachloride.

and a host of allied alimentary substances are also included C2CIA Tetrachlor-ethylene.

in this group, though their exact relationship to the typi.

cal members is not as yet clearly established. Now, sugar CHCl 0, Trichlor-acetic acid.

has been obtained by Berthelot from glycerine, which is C,H,02 Acetic acid.

itself, as I have said, obtainable by purely inorganic The disulphide of carbon, produced by the direct com- means ; so that, in one sense, sugаr may be added to the bination of sulphur and carbon, is converted, by treatment list of artificially produced organic compounds. Still the with chlorine, into tetrachloride of carbon ; this, by heat- means employed for effecting the conversion of the glyceing to redness, into tetrachlor-ethylene ; this, by the action rine-namely, the action of putrifying animal tissue-must of moist chlorine, into trichlor-acetic acid ; and this, by prevent our regarding the resultant sugar as being strictly means of nascent hydrogen, into ordinary acetic acid. of inorganic origin ; although it is formed exclusively out By arresting the hydrogenation at a certain point, and of the glycerine, the animal tissue not contributing any treating the so-formed monochlor-acetic acid C,H,C102, actual material to its formation. However, if sugar has with ammonia, we obtain glycocine, whereas by treating not yet been obtained by a satisfactory process, the recent it with methylamine we obtain sarcosine, which, in com- formation of strictly allied bodies, such as the propylbination with urea, constitutes kreatine, a compound, how- phycite of Carius, together with our increasing knowledge ever, that has not yet beeno btained artificially.

of the metamorphic relations of sugar itself, assures us Thus, among 2-carbon products of the animal and vege- that an unexceptionable means for producing this important table kingdom, that have been obtained by strictly mineral alimentary principle cannot much longer escape us. processes, may be mentioned alcohol, triethylamine, taurine, The transformation of fatty into aromatic compounds acetic acid, glycocine, sarcosine, and last, though not least has not yet been accomplished according to any definite important, oxalic acid; which results from the oxidation reaction ; but both phenene C&He, and phenol or carbolic of alcohol, acetic acid, and glycolic acid, &c., and is pro- acid C.H.0, are producible by transmitting the vapour of ducible synthetically from the mono-carbon formic and alcohol or fousel oil through red-hot tubes. From the carbonic acids.

former of these bodies we readily obtain aniline or phenyl. By means of the general processes to which I directed amine C H,N, which is reconvertible into both phenene your attention some time back, as well as by certain and phenol. special processes, it is easy to pass from the 2-carbon to The 7-carbon fatty acid and alcohol are usually obtained the 3-carbon group, upon which, however, we must rest from castor oil. So far as I know, they have not been satisfied with bestowing a very cursory glance. It com- produced artificially from inorganic materials, but unprises among its members glycerine Czł,03, the basic doubtedly could be so produced at any moment.

With principle of the true fats, whether of vegetable or animal the 7-carbon aromatic compounds the case is different. origin. Also lactic acid C2H603, an important constituent By the general processes already referred to, phenene has of the juice of flesh, and a product of that fermentation of been converted into benzoic acid CyH60, by Harnitzky grape-sugar and milk-sugar which is set up by putrefying and Kekulé, and phenol into salicic acid C,H603, by curd. We have also the chief constituents of essential oil | Kolbe. Benzoic acid readily yields benzoic aldehyd or of garlic or allyl-sulphide (C2H3)2S, and of essential oil of essential oil of bitter almonds, and also glyco-benzoic or mustard or allyl-sulphocyanate (C,H3) HCNS, to be in- hippuric acid. Salicic acid, again, is readily oxidisable cluded in the list of artificially-produced members of the into gallic acid, of which tannin constitutes the natural propionic family.

glucoside, as shown by the following decomposition :Passing on to the 4-carbon group, we have first butyric

Glucose. acid C 7.12, a product of the destructive metamorphosis C2H,2017 31,0 C&H 206 3C,1606 of sugar, mannite, &c. Combined with alcohol it forms butyric ether or essential oil of pine-apple, while combined essential oil of wintergreen, salicic aldehyd or essential

From salicic acid we may also obtain methylsalicate or with glycerine it forms that constituent of ordinary butter oil of spirea, and saligenine or salicylic alcohol, a comwhich is known as butyrine. Butyric is readily convertible into succinic acid c,1,0, which bears to it the pound frequently mentioned in my second lecture as a same relation that oxalic bears to acetic acid, and probably indeed, a glucoside of saligenine, much in the same way

constituent residue of salicine and populine-salicine being, the most frequent artificial product of the oxidation of fatty that tannin is a glucoside of gallic acid, thus :

From succinic acid it is easy to procure in succession the well-known vegetable products, malic acid


Glucose. Saligenine. C 460s, and tartaric acid C 7.0. The succinic and malic C12H180, + H2O C6H12O6 + C,H,Oz. acids are very intimately associated with, and readily con

Moreover, tyrosine,-a very remarkable product of tissue vertible into, one another. Thus asparagine CH.N,03, metamorphosis—though not yet produced from salicic acid, the crystalline principle of asparagus and other etiolated has much the same relation thereto that leucine has to plants, yields one or other of these acids, according to the caproic, and sarcosine and glycocine have to acetic acid, treatment to which it is subjected.

being, indeed, the ethyl-ammoniated form of salicic acid. The s-carbon compounds of artificial origin are of less Another 7-carbon compound of artificial production, and general interest.

I may mention fuusel oil or amyl- of great interest in an industrial point of view, is benzoene, alcohol C3H120, and valeric or valerianic acid C,H11002, or toluol C,Hg, which Fittig and Tollens have recently a product originally obtained from essential oil of valerian. obtained from phenene or benzol CoH. Starting from By combining amyl-alcohol with acetic acid we procure these two bodies, we may procure all the so-called coalthe pear flavour, and by combining it with valeric acid tar colours, with the brilliancy and variety of which most the apple or quince flavour used in confectionery, which of us are now familiar. The red base or rosaniline are probably identical with the essential oils existing in C2H,,N3, the violet base or triethylrosaniline C26H31N 39 the ripe fruits. Again, by combining valeric acid with and the blue base or triphenylrosaniline C38H31 N3, being glycerine we produce valerine, a constituent of whale oil. producible in this way from their constituent elements,

Of the 6-carbon fatty compounds which have been furnish admirable illustrations of the constructive powers artificially obtained, the most interesting are caproic acid of modern organic chemistry. C.H220, and leucic acid CoH_203. Caproic acid is met Thus have I illustrated to you the mode in which



Gallic acid.





Academy of Sciences Notices of Books.


Sept, 1, 1865.

chemists can nowadays, without any recourse to vitality, oil, after a time, oxidised faster in the dark than when build up primary molecules containing as many as seven exposed to coloured or white light. Oil heated. in atmoatoms of carbon, either from carbonic acid, water, and spheric air oxidised much more rapidly than cold oil. The ammonia, the materials out of which living organisms con- oxidation may be accelerated without heat by adding some struct identical or similar molecules, or else from the elemen- oil already oxidised. tary substances, carbon, hydrogen, oxygen, and nitrogen, M. Blomstrand presented a “ Note on the Metals of the upon which living organisms can exert no plastic action what. Tantalum Group." According to the author, only two ever. I might even proceed further, but should then be metals exist in this group, Niobium and Tantalum. The obliged to depart from that regular sequence I have acids also are only two in number, di- or tetratomic: hitherto followed. Moreover, my object has been rather tantalic acid Tao, or fae, and niobic acid Nb0, or Nbez. to illustrate to you the general mode of procedure than Rose's white hyponiobic chloride is an oxychloride, to make known to you the utmost limits that have as yet Nb C1,0, or the double. Hyponiobic acid prepared by been attained. Of the three great classes of alimentary the decomposition of the oxychloride is true niobic acid, substances, the oleaginous are quite, and the saccharine NbO2. Kobell's dianic acid is, without doubt, niobic acid, almost within our reach. The albuminous, indeed, are still either pure or perhaps inixed with a little tantalic acid, far beyond us; and no wonder, since their very constitu- too small in quantity to interfere with the reaction with tion is at present not only unknown, but unsuspected. In tin which Kobell considered characteristic of dianium, and their case, however, as in that of many other bodies, so which is also common to niobium. The author criticises soon as we succeed in unravelling the mystery of their M. Marignac's paper on the hyponiobic compounds, sugnatural composition, so soon may we aspire confidently gesting that the material M. Marignac experimented with to the work of their artificial reconstruction.

was not pure, tantalum being present with the niobium. Only a few words more, which I will borrow from my As we recently mentioned, Blomstrand has fixed the friend Dr. Frankland. "It would be difficult,” said he equivalent of true niobium at 39 (Nb = 78). to conclude a subject like the present without some Two other papers we may dispose of very shortly. M. notice of the considerations which naturally suggest them- Pécholier writes, that the reason absinthe produces worse selves regarding the possibility of economically replacing effects than other alcoholic drinks of equal strength is, natural processes by artificial ones in the formation of that the liquor is usually taken on an empty stomach. organic compounds. At present, the possibility of doing M. Donnet has made a microscopic examination of rotten this only attains to probability in the case of rare and eggs, to ascertain whether the putrefaction was caused by, exceptional products of animal and vegetable life. By no or developed, infusoria. He found no trace of organisms processes at present known could we produce sugar, at any stage of the putrefaction. This is an important glycerine, or alcohol from their elements at one hundred fact for the opponents of spontaneous generation. times their present cost, as obtained through the agency of vitality. But, although our present prospects of rival.

NOTICES OF BOOKS, ling vital processes in the economic production of staple organic compounds, such as those constituting the food of man, are exceedingly slight, yet it would be rash to pro- Diamonds and Precious Stones : their History, Value, and nounce their ultimate realisation impossible. It must be Distinguishing Characteristics : with Simple Tests for remembered that this branch of chemistry is as yet in its their Identification. By HARRY EMANUEL, F.R.G.S. merest infancy; that it has hitherto attracted the attention London : Hotten. 1865. of but few minds; and further, that many analogous substi- A COMPLETE account of diamonds and precious stones in tutes of artificial for natural processes have been achieved. relation to chemistry, geology, art, morals, and political

In such cases where contemporaneous natural economy, would form one of the most interesting books agencies have been superseded, we have almost invariably ever written. The author of the work under notice does drawn upon that grand store of force collected by the not pretend to anything so ambitious as this, and yet has plants of bygone ages and conserved in our coal-fields."

produced a book of very considerable value. The scientific

account of the sereral stones, indeed, is in most cases imACADEMY OF SCIENCES.

perfect, and in many inexact; art is scarcely noticed, and

the special history is, we fear, not always to be relied August 21.

upon; but, in spite of this, the general reader will find M. DAMOUR presented a memoir “ On the Chemical Com- much that is novel and interesting, and those who wish position of the Stone Implements of Pre-historic Times." for commercial information much that is valuable. In this first part of the memoir the author gives a very Diamonds and precious stones have in all ages possessed good account of quartz, agate, flint, jaspar, obsidian, and a high exchangeable value—not entirely, it would seem, fibrolite, all well-known substances that have been em- from their rarity: Ancient superstitions ascribed to certain ployed in the manufacture of stone implements. The stones occult virtues which modern intelligence would account of the examination of the implements is to come, appear to not altogether discredit. The author of this we suppose, in the next part.

work, in his evidence in the case Emanuel o. Wilbraham, M. Cloëz contributed a second memoir “ On the Oxida- said that it was customary in these days for a gentleman tion of Fatty Vegetable Oils." In this memoir he treats of when engaged to present his fiancée with three rings, an the influence of light and heat on the oxidation. The emerald, a ruby, and a diamond. These, which would at author's results are of much interest. He exposed oils to first sight appear merely as offerings to the lady's vanity, the air in colourless glass vessels, and also in vessels of may perhaps have another signification. For we learn red, yellow, green, and blue glass, and also left some oil from this and other books that the emerald was regarded exposed to air in total darkness. After ten days' exposure as preservative of female chastity, while the ruby was the increase of weight was greatest in the colourless glass supposed to ward off evil company and unpleasant dreams, vessel ; it was rather less in the blue glass ; was very small and the diamond was potent against all sorts of poisons. in the red, yellow, and green; and no increase of weight Potent or not, diamonds and rubies are now of more value at all was observed in the oil exposed in the dark. Like than they ever were, and, as the author hopes in his results were found after twenty days; but after thirty preface, this book “ will prove useful to the merchant in days' exposure the results were somewhat different. The supplying him without trouble with the distinguishing increase of weight was greater in the coloured glasses than characteristics of each gem, and to the amateur as affordin the uncoloured, green showing the largest increase after ing him simple and easy means of distinguishing the false 150 days' exposure. It is worthy of notice that poppy from the real, and the valuable from the worthless."

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