DIVISION II.—PTOMAINES—TOXINES.

§ 648. Definition of a Ptomaine.—A ptomaine may be considered as a basic chemical substance derived from the action of bacteria on nitrogenous substances. If this definition is accepted, a ptomaine is not necessarily formed in the dead animal tissue; it may be produced by the living, and, in all cases, it is the product of bacterial life. A ptomaine is not necessarily poisonous; many are known which are, in moderate doses, quite innocuous.

When Selmi’s researches were first published there was some anxiety lest the existence of ptomaines would seriously interfere with the detection of poison generally, because some were said to be like strychnine, others like colchicine, and so forth. Farther research has conclusively shown that at present no ptomaine is known which so closely resembles a vegetable poison as to be likely in skilled hands to cause confusion.

Isolation of Ptomaines.

§ 649. Gautier’s [653] Process.—The liquid is acidified with oxalic acid, warmed, filtered, and distilled in a vacuum.

[653] Ptomaines et Leucomaines, E. J. A. Gautier, Paris, 1886.

In this way pyrrol, skatol, phenol, indol, and volatile fatty acids are separated and will be found in the distillate. The residue in the retort is treated with lime, filtered from the precipitate that forms, and distilled in a vacuum, the distillate being received in weak sulphuric acid. The bases accompanied with ammonia distil over. The distillate is now neutralised by sulphuric acid [654] and evaporated nearly to dryness, separating the mother liquid from sulphate of ammonia, which crystallises out. The mother liquids are treated with absolute alcohol, which dissolves the sulphates of the ptomaines. The alcohol is got rid of by evaporation, the residue treated with caustic soda, and the bases shaken out by successive treatment with ether, petroleum ether, and chloroform. The residue remaining in the retort with the excess of lime is dried, powdered, and exhausted with ether; the ethereal extract is separated, evaporated to dryness, the dry residue taken up in a little water, slightly acidulated, and the bases precipitated by an alkali.

[654] The first acid apparently is so dilute that the distillate more than neutralises it, hence more sulphuric acid is added to complete neutralisation.

§ 650. Brieger’s Process.—Brieger [655] thus describes his process:—

[655] Untersuchungen über Ptomaine, Theil iii., Berlin, 1886.

“The matters are finely divided and boiled with water feebly acidulated with hydrochloric acid.

“Care must be taken that on boiling, the weak acid reaction must be retained, and that this manipulation only lasts a few minutes.

“The insoluble portion is filtered off, and the filtrate evaporated, either in the gas-oven or on the water-bath, to syrupy consistency. If the substances are offensive, as alcoholic and watery extracts of flesh usually are, the use of Bocklisch’s simple apparatus (see [diagram]) is to be recommended. The filtrate to be evaporated is placed in a flask provided with a doubly perforated caoutchouc cork carrying two bent tubes; the tube b terminates near the bottom of the flask, while the tube a terminates a little above the level of the fluid to be evaporated. The tube a is connected with a water pump which sucks away the escaping steam. In order to avoid the running back of the condensed water forming in the cooler part of the tube, the end of the tube a is twisted into a circular form. Through the tube b, which has a fine capillary bore, a stream of air is allowed to enter, which keeps the fluid in constant agitation, continually destroying the scum on the surface, and avoiding sediments collecting at the bottom, which may cause fracture of the flask. According to the regulation of the air current, a greater or smaller vacuum can be produced. The fluid, evaporated to the consistency of a syrup, is treated with 96 per cent. alcohol, filtered, and the filtrate precipitated with lead acetate.

“The lead precipitate is filtered off, the filtrate evaporated to a syrup, and the syrup again treated with 96 per cent. alcohol. This is again filtered, the alcohol got rid of by evaporation, water added, the lead thrown down by SH₂, and the fluid, after the addition of a little hydrochloric acid, evaporated to the consistence of a syrup; this syrup is exhausted with 96 per cent. alcohol, and precipitated with an alcoholic solution of mercury chloride. The mercury precipitate is boiled with water, and by the different solubility of the mercury salts of certain ptomaines some separation takes place. If it is suspected that some of the ptomaines may have been separated with the lead precipitate, this lead precipitate can be decomposed by SH₂ and investigated. I have only (says Brieger) in the case of mussels been able to extract from the lead precipitate small quantities of ptomaines.

“The mercury filtrate is freed from mercury and evaporated, the excess of hydrochloric acid being carefully neutralised by means of soda (for it must only be slightly acid); then it is again treated with alcohol, so as to separate as much as possible the inorganic constituents. The alcoholic extract is evaporated, dissolved in a little water, neutralised with soda, acidulated with nitric acid, and precipitated with phospho-molybdic acid. The phospho-molybdic acid precipitate is decomposed with neutral lead acetate, which process may be facilitated by heating on the water-bath. After getting rid of the lead by treatment with SH₂, the fluid is evaporated to a syrup and alcohol added, by which process many ptomaines may be eliminated as hydrochlorates; or they can be converted into double salts (of platinum or gold) for the purpose of separation. In the filtrate from phospho-molybdate, ptomaines may also be found by treating with lead acetate to get rid of the phospho-molybdic acid, and then adding certain reactives. Since it is but seldom that the hydrochlorates are obtained in a state of purity, it is preferable to convert the substance separated into a gold or platinum salt or a picrate, since the greater or less solubility of these compounds facilitates the purification of individual members; but which reagent is best to add, must be learned from experience. The melting-point of these salts must always be taken, so that an idea of their purity may be obtained. It is also to be noted that many gold salts decompose on warming the aqueous solution; this may be avoided by the addition of hydrochloric acid. The hydrochlorates of the ptomaines are obtained by decomposing the mercury, gold, or platinum combinations by the aid of SH₂, while the picrates can be treated with hydrochloric acid and shaken up with ether, which latter solvent dissolves the picric acid.

“Considerable difficulty in the purification of the ptomaines is caused by a nitrogenous, amorphous, non-poisonous, albumin-like substance, which passes into all solutions, and can only be got rid of by careful precipitation with an alcoholic solution of lead acetate, in which it is soluble in excess. This albuminoid forms an amorphous compound with platinum, and acts as a strongly reducing agent (the platinum compound contains 29 per cent. platinum). When this albuminoid is eliminated, then the hydrochlorates or the double salts of the ptomaines crystallise.”

§ 651. The Benzoyl Chloride Method.—The fatty diamines in dilute aqueous solutions, shaken with benzoyl chloride and soda, are converted into insoluble dibenzoyl derivatives; these may be separated from benzamide and other nitrogenous products by dissolving the precipitate in alcohol, and pouring the solution into a large quantity of water.[656] Compounds which contain two amido groups combined with one and the same carbon atom, do not yield benzoyl derivatives when shaken with benzoyl chloride and soda. Hence this reaction can be utilised for certain of the ptomaines only. The solution must be dilute, because concentrated solutions of creatine, creatinine, and similar bodies also give precipitates with benzoyl chloride; no separation, however, occurs unless these bodies are in the proportion of five per thousand.

[656] L. V. Udrànsky and Baumann, Ber., xxi. 2744.

The process is specially applicable for the separation of ethylenediamine, pentamethylenediamine (cadaverine), and tetramethylenediamine (putrescine) from urine. In a case of cystinuria Udrànsky and E. Baumann [657] have found 0·24 grm. of benzoyltetramethylenediamine, 0·42 grm. of benzoylpentamethylenediamine in a day. Diamines are absent in normal fæces and urine. Stadthagen and Brieger [658] have also found, in a case of cystinuria diamines, chiefly pentamethylenediamine.

[657] L. V. Udrànsky and Baumann, Zeit. f. physiol. Chem., xiii. 562.

[658] Arch. pathol. Anatom., cxv. p. 3.

The operation is performed by making the liquid alkaline with soda, so that the alkalinity is equal to about 10 per cent., adding benzoyl chloride, shaking until the odour of benzoyl chloride disappears, and then filtering; to the filtrate more benzoyl chloride is added, the liquid shaken, and, if a precipitate appears, this is also filtered off, and the process repeated until all diamines are separated.

The precipitate thus obtained is dissolved in alcohol, and the alcoholic solution poured into a considerable volume of water and allowed to stand over night; the dibenzoyl compound is then usually found to be in a crystalline condition. The compound is crystallised once or twice from alcohol or ether, and its melting-point and properties studied. Mixtures of diamines may be separated by their different solubilities in ether and alcohol.

A solution of 0·00788 grm. of pentamethylenediamine in 100 c.c. of water gave 0·0218 grm. of the dibenzoyl-derivative when shaken with benzoyl chloride (5 c.c.) and 40 c.c. of soda (10 per cent.) and kept for twenty-four hours. In a second experiment with a similar solution only 0·0142 grm. of dibenzoyl-derivative was obtained;[659] hence the process is not a good quantitative process, and, although convenient for isolation, gives, so far as the total amount recovered is concerned, varying results.

[659] Ber., xxi. 2744.

§ 652. The Amines.—The amines are bases originating from ammonia and built on the same type. Those that are interesting as poisons are monamines, diamines, and the quaternary ammonium bases.

Considered as compound ammonias, the amines are divided into primary or amide bases, secondary or imid bases, and tertiary or nitrile bases, according as to whether one, two, or three atoms of hydrogen have been displaced from the ammonia molecule by an alkyl; for instance, methylamine NH₂CH₃ is a primary or amide base, because only one of the three atoms of H in NH₃ has been replaced by methyl; similarly, dimethylamine is a secondary or imid base, and trimethylamine is a tertiary or nitrile base.

The quaternary bases are derived from the hypothetical ammonium hydroxide NH₄OH, as, for example, tetraethyl ammonium hydroxide (C₂H₅)₄N,OH.

The diamines are derived from two molecules of NH, and therefore contain, instead of one molecule of nitrogen, two molecules of nitrogen; in two molecules of ammonia there are six atoms of hydrogen, two, four, or six of which may be replaced by alkyls; as, for example,


Ethylenediamine.	Diethylenediamine.	Triethylenediamine.

The monamines are similar to ammonia in their reactions; some of them are stronger bases; for instance, ethylamine expels ammonia from its salts. The first members of the series are combustible gases of pungent odour, and easily soluble in water; the higher homologues are fluids; and the still higher members solids.

The hydrochlorides are soluble in absolute alcohol, while chloride of ammonium is insoluble; this property is taken advantage of for separating amines from ammonia. The amines form double salts with platinic chloride; this is also utilised for recognition, for the purpose of separation, and for purification; for instance, ammonium-platinum-chloride on ignition yields 43·99 per cent. of platinum, and methylamine-platinum-chloride yields 47·4 of platinum. It is comparatively easy to ascertain whether an amine is primary, secondary, or tertiary.

The primary and secondary amines react with nitrous acid, but not the tertiary; the primary amines, for instance, are converted into alcohols, and there is an evolution of nitrogen gas; thus methylamine is decomposed into methyl alcohol, nitrogen, and water.

CH₃NH₂ + (OH)NO = CH₃(OH) + N₂ + H₂O.

The secondary amines, treated in the same way, evolve no nitrogen, but are converted into nitrosamines; thus dimethylamine, when treated with nitrous acid, yields nitrosodimethylamine,

(CH₃)₂NH + (OH)NO = (CH₃)₂(NO)N + H₂O;

and the nitrosamines respond to the test known as Lieberman’s nitroso-reaction, which is thus performed:—The substance is dissolved in phenol and a few drops of concentrated sulphuric acid added. The yellow colour at first produced changes into blue by adding to the acid liquid a solution of potash.

The primary amines, and the primary amines alone, treated with chloroform and alcoholic potash, yield the peculiarly offensive smelling carbylamine or isonitrile (Hofmann’s test),

V
NH₂(CH₃) + CHCl₃ + 3KOH = C≣N	-CH₃ + 3KCl + 3H₂O.

Again the primary bases, when treated with corrosive sublimate and carbon disulphide, evolve sulphuretted hydrogen, and mustard oil is produced, e.g.,

NH₂(C₂H₅)	+	CS₂	=	CS=N-C₂H₅	+	H₂S.
Ethylamine.				Ethylmustard oil.

Where a sufficient quantity of an amine is obtained, the primary, secondary, or tertiary character of the amine may be deduced with certainty by treating it with methyl or ethyl iodide.

A molecule of the base is digested with a molecule of methyl iodide and distilled with potash; the distillate is in the same manner again treated with methyl iodide and again distilled; and the process is repeated until an ammonium base is obtained, which will take up no more iodide. If three methyl groups were in this way introduced, the original substance was primary, if two, secondary, if one, tertiary.

The quaternary bases, such as tetraethyl ammoniumoxhydrate, decompose, on heating, into triethylamine and ethylene; the corresponding methyl compound in like manner yields trimethylamine and methyl-alcohol.

On the other hand, the primary, secondary, and tertiary bases do not decompose on heating, but volatilise without decomposition.

The chief distinctions between these various amines are conveniently put into a tabular form as follows:—

	Primary, NH₂R.	Secondary, NHR₂.	Tertiary, NR₃.	Quaternary, NR₄(OH).
On treating with methyl iodide it takes up the following number of methyl groups,	3	2	1	...
Reaction with nitrous acid,	Decomposes with evolution of nitrogen gas.	Formation of nitrosamine.	...	...
Mustard oil, &c., on treatment with CS₂ and sublimate,	Mustard oil formed.	...	...	...
Chloroform and alcoholic potash,	Formation of carbylamine.	...	...	...
Effect of strong heat,	Sublimes.	Sublimes.	Sublimes.	Decomposes.
On addition of acids,	Combines to form salts.	Combines to form salts.	Combines to form salts.	...

§ 653. Methylamine, CH₃NH₂.—This is a gas at ordinary temperatures; it is inflammable, and possesses a strong ammoniacal odour. It has been found in herring brine, and is present in cultures of the comma bacillus; it has also been found in poisonous sausages, but it is not in itself toxic.

It forms crystalline salts, such as, for example, the hydrochloride, the platinochloride (Pt = 41·4 per cent.), and the aurochloride (Au = 53·3 per cent. when anhydrous). The best salt for estimation is the platinochloride, insoluble in absolute alcohol and ether.

§ 654. Dimethylamine, (CH₃)₂NH.—Dimethylamine is also a gas; it has been found in various putrefying substances. It forms crystalline salts, such as the hydrochloride, the platinochloride (Pt = 39·1 per cent.), and an aurochloride (Au = 51·35 per cent.). It is not poisonous.

In Brieger’s process it may occur in both the mercuric chloride precipitate and filtrate. From cadaverine it may be separated by platinum chloride; cadaverine platinochloride is with difficulty soluble in cold water and crystallises from hot water, while dimethylamine remains in the mother liquor. From choline it may be separated by recrystallising the mercuric precipitate from hot water. From methylamine it may be separated by converting into chloride and extracting with chloroform; dimethylamine chloride is soluble, methylamine chloride insoluble in chloroform.

§ 655. Trimethylamine, (CH₃)₃N.—Trimethylamine in the free state is an alkaline liquid with a fishy odour, boiling at 9·3°; it is not toxic save in large doses.

It occurs in a great variety of plants, and is also found in putrefying substances. It is a product of the decomposition of choline, betaine, and neuridine, when these substances are distilled with potash.

In Brieger’s process, if an aqueous solution of mercuric chloride is used as the precipitant, trimethylamine (if present) will be almost entirely in the filtrate, from which it can be obtained by getting rid of the mercury by SH₂, filtering, evaporating to dryness, extracting with alcohol, and precipitating the alcoholic solution with platinic chloride. It forms crystalline salts with hydrochloric acid, platinum chloride, and gold chloride; the platinum double salt yields 37 per cent. of platinum, the gold salt 49·4 per cent. gold. The gold salt is easily soluble, and this property permits its separation from choline, which forms a compound with gold chloride soluble with difficulty.

§ 656. Ethylamine, C₂H₅NH₂.—Ethylamine is in the free state an ammoniacal liquid boiling at 18·7°. It is a strong base, miscible with water in every proportion. It has been found in putrefying yeast, in wheat flour, and in the distillation of beet sugar residues. It is not poisonous; the hydrochloride forms deliquescent plates melting at 76°-80°; the platinochloride contains 39·1 per cent. of platinum, and the gold salt 51·35 per cent. of gold. In other words, the same percentages as the corresponding salts of dimethylamine, with which, however, it cannot be confused.

§ 657. Diethylamine, (C₂H₅)₂NH, is an inflammable liquid boiling at 57·5°; it forms salts with hydrochloric acid, platinum and gold, &c.; the gold salt contains 47·71 per cent. of gold, and its melting-point is about 165°.

§ 658. Triethylamine, (C₂H₅)₃N, is an oily base but slightly soluble in water, and boiling at 89°-89·5°. It gives no precipitate with mercuric chloride in aqueous solution; it forms a platinochloride containing 31·8 per cent. of platinum. It has been found in putrid fish.

§ 659. Propylamine.—There are two propylamines; one, normal propylamine, CH₃CH₂.CH₂.NH₂, boiling at 47°-48°, and iso-propylamine, (CH₃)₂CH.NH₂, boiling at 31·5°; both are ammoniacal fish-like smelling liquids. The hydrochloride of normal propylamine melts at 155°-158°, and iso-propylamine chloride melts at 139·5°.

It has been found in cultures of human fæces on gelatin. None of the above amines are sufficiently active in properties to be poisonous in the small quantities they are likely to be produced in decomposing foods.

§ 660. Iso-amylamine, (CH₃)₂CH.CH₂.CH₂.NH₂, is a colourless alkaline liquid, possessing a peculiar odour. It boils at 97°-98°. It forms a deliquescent hydrochloride. The platinochloride crystallises in golden yellow plates.

Iso-amylamine occurs in the putrefaction of yeast, and is a normal constituent of cod-liver oil. It is intensely poisonous, producing convulsions.

Diamines.

§ 661. Rate of Formation of Diamines.—Diamines are formed in putrefactive processes, generally where there is abundance of nitrogen. Garcia [660] has attempted to trace the rates at which they are formed by allowing meat extracts to decompose, precipitating by benzoyl chloride (see [p. 487]) the dibenzoyl compound, and weighing; the following were the results obtained:—

[660] Zeit. f. physiol. Chemie, xvii. 6. 571.

Time.	Weight of benzoyl compound.
24 hours,	0·56	grm.
2 days,	0·75	„
3 days,	0·82	„
4 days,	0·73	„
5 days,	0·57	„
6 days,	0·58	„

§ 662. Ethylidenediamine.—Brieger found in putrid haddock, in the filtrate from the mercury chloride precipitate:—gadinine, neuridine, a base isomeric with ethylenediamine C₂H₈N₂ (but which Brieger subsequently more or less satisfactorily identified with ethylidenediamine), muscarine, and triethylamine; these bases were separated as follows:—

The filtrate from the mercury chloride solution was freed from mercury by SH₂, evaporated to a syrup, and then extracted with alcohol. From the alcoholic solution platinum chloride precipitated neuridine, this was filtered off, the filtrate freed from alcohol and platinum, and the aqueous solution concentrated to a small volume and precipitated with an aqueous solution of platinum chloride; this precipitated ethylidene platinum chloride. The mother liquor from this precipitate was concentrated on the water-bath, and, on cooling, the platinochloride of muscarine crystallised out. From the mother liquor (freed from the crystals), on standing in a desiccator, the gadinine double salt crystallised out, and from the mother liquor (freed from gadinine after removal of the platinum by SH₂) distillation with KHO recovered trimethylamine.

From the platinochloride of ethylenediamine, the chloride can be obtained by treating with SH₂, filtering, and evaporating; by distilling the chloride with a caustic alkali, the free base can be obtained by distillation.

Ethylidenediamine is isomeric with ethylenediamine, but differs from it in the following properties:—ethylidenediamine is poisonous, ethylenediamine is non-poisonous.

Ethylenediamine forms a platinochloride almost insoluble in hot water, while the ethylidene salt is more easily soluble. The properties of the gold salts are similar, ethylenediamine forming a difficultly soluble gold salt, ethylidene a rather soluble gold salt.

Ethylidenediamine forms a hydrochloride, C₂H₈N₂2HCl, crystallising in long glistening needles, insoluble in absolute alcohol, rather soluble in water. The hydrochloride gives precipitates in aqueous solution with phospho-molybdic acid, phospho-antimonic acid, and potassium bismuth iodide; the latter is in the form of red plates.

The platinochloride, C₂H₈N₂2HCl.PtCl (Pt = 41·5 per cent.), is in the form of yellow plates, not very soluble in cold water.

Ethylidenediamine, when subcutaneously injected into guinea-pigs, produces an abundant secretion from the mucous membranes of the nose, mouth, and eyes. The pupils dilate, and the eyeballs project. There is acute dyspnœa; death takes place after some twenty-four hours, and the heart is stopped in diastole.

Trimethylenediamine is believed to have been isolated by Brieger from cultivations in beef broth of the comma bacillus.

It occurs in small quantity in the mercuric chloride precipitate, and is isolated by decomposing the precipitate with SH₂, evaporating the filtrate from the mercury sulphide to dryness, taking up the residue with absolute alcohol, and precipitating by an alcoholic solution of sodium picrate. The precipitate contains the picrate of trimethylenediamine, mixed with the picrates of cadaverine and creatinine. Cadaverine picrate is insoluble in boiling absolute alcohol, the other picrates soluble; so the mixed picrates are boiled with absolute alcohol, and the insoluble cadaverine filtered off. Next, the picrates of creatinine and trimethylenediamine are freed from alcohol, the solution in water acidified with hydrochloric acid, the picric acid shaken out by treatment with ether, and then the solution precipitated with platinum chloride; the platinochloride of trimethylenediamine is not very soluble, while creatinine easily dissolves; so that separation is by this means fairly easy.

It also gives a difficultly soluble salt with gold chloride.

The picrate consists of felted needles, melting-point 198°. Phospho-molybdic acid gives a precipitate crystallising in plates; potassium bismuth iodide gives dark coloured needles.

It produces in animals violent convulsions and muscular tremors; but the substance has hitherto been obtained in too small a quantity to be certain as to its identification and properties.

§ 663. Neuridine, C₅H₁₄N₂.—Neuridine is a diamine, and is apparently the most common basic product of putrefaction; it has been obtained from the putrefaction of gelatin, of horseflesh, of fish, and from the yelk of eggs. It is usually accompanied by choline, from which it can be separated by converting the bases into hydrochlorides, choline hydrochloride being soluble in absolute alcohol, neuridine scarcely so. Brieger isolated neuridine from putrid flesh by precipitating the watery extract with mercuric chloride. He decomposed the mercury precipitate with SH₂, and, after having got rid of the sulphide of mercury by filtration, he concentrated the liquid to a small bulk, when a substance separated in crystals similar in form to urea; this was purified by recrystallisation from absolute alcohol, and converted into the platinum salt.

Another method which may be used for the separation and purification of neuridine is to dissolve it in alcohol and precipitate with an alcoholic solution of picric acid; the picrate may be decomposed by treatment with dilute mineral acid, and the picric acid removed by shaking with ether.

The free base has a strong seminal odour. It is gelatinous, and has not been crystallised. It is insoluble in ether and in absolute alcohol, and not readily soluble in amyl alcohol. It gives white precipitates with mercuric chloride, neutral and basic lead acetates. It does not give Hofmann’s isonitrile reaction. When distilled with a fixed alkali, it yields di- and trimethylamine.

The hydrochloride, C₅H₁₄N₂2HCl, crystallises in long needles, which are insoluble in absolute alcohol, ether, benzol, chloroform, petroleum ether, and amyl alcohol; but the hydrochloride is very soluble in water and in dilute alcohol.

The hydrochloride gives no precipitate with mercuric chloride, potass-mercuric iodide, potass-cadmium iodide, iodine and iodide of potassium, tannic acid, ferricyanide of potassium, ferric chloride, and it does not give any colour with Fröhde’s reagent.

On the other hand, phosphotungstic acid, phospho-molybdic acid, picric acid, potass-bismuth iodide, platinum chloride, and gold chloride all give precipitates.

Neuridine hydrochloride is capable of sublimation, and at the same time it is decomposed, for the sublimed needles show red or blue colours.

Neuridine platinochloride, C₅H₁₄N₂2HCl.PtCl₄, yields 38·14 per cent. of platinum; it crystallises in flat needles, soluble in water, from which it is precipitated on the addition of alcohol.

The aurochloride has the formula C₅H₁₄N₂2HCl2AuCl₃; it is rather insoluble in cold water, and crystallises in bunches of yellow needles. On ignition, it should yield 41·19 per cent. of gold.

The picrate, C₅H₁₄N₂,2C₆H₂(NO₂)₃OH, is almost insoluble in cold water, and crystallises in needles. It is not fusible, but decomposes at about 230°.

Neuridine is not poisonous.

§ 664. Cadaverine (Pentamethylenediamine, C₅H₁₄N₂=NH₂CH₂-CH₂-CH₂-CH₂CH₂NH₂) is formed in putrid animal matters, and in cultures of the genus Vibrio. It has been found in the urine and fæces in cases of cystinuria, and Roos [661] has separated it by the benzoyl-chloride method from the fæces of a patient suffering from tertian ague. It may be formed synthetically by dissolving trimethylcyanide in absolute alcohol, and then reducing by sodium (Mendius’ reaction).

[661] Zeit. f. physiol. Chemie, xvi., 1892.

Cadaverine is a thick, clear, syrupy liquid, with a peculiar coniine- as well as a semen-like odour. It absorbs eagerly CO₂ from the air, and ultimately is converted into a solid crystalline mass. It volatilises with the steam when boiled with water, and may be distilled in the presence even of the caustic alkalies and the alkaline earths without decomposition. It does not give oil of mustard when treated with CS₂ and mercuric chloride, nor does it give with chloroform and alcoholic potash, carbylamine (isonitrile). If dehydrated by KHO, it boils at from 115°-120° (Brieger).[662]

[662] Brieger has also given to the pure base a boiling-point of 175°.

When cadaverine is treated with methyl iodide, two atoms of hydrogen may be replaced with methyl, forming the base C₅H₁₂(CH₃)₂N₂; the platinochloride of this last base crystallises in long red needles.

Cadaverine forms well-defined crystalline salts as well as compounds with metals.

Cadaverine hydrochloride, C₅H₁₄N₂2HCl, crystallises in needles which are deliquescent, or it may be obtained from an alcoholic solution in plates. The crystals are insoluble in absolute alcohol, but readily soluble in 96 per cent. alcohol. Putrescine hydrochloride, on the other hand, is with difficulty soluble in alcohol of that strength; hence the two hydrochlorides can be separated by taking advantage of their difference in solubility in 96 per cent. alcohol; but the better method for separation is the benzoyl-chloride process ([p. 487]). On dry distillation, cadaverine hydrochloride decomposes into NH₃,HCl and piperidine C₅H₁₁N. The compound with mercury chloride—C₅H₁₄N₂2HCl,4HgCl₂ (Hg = 63·54 per cent.); melting-point, 214°-216°—is insoluble in alcohol and in cold water; this property is also useful to separate it from putrescine, the mercury compound of which is soluble in cold water. The platinochloride, C₅H₁₄N₂2HCl,PtCl₄ (Pt = 38·08 per cent.), crystallises in dirty red needles; but, by repeated crystallisation, it may be obtained in clear chrome yellow, short, octahedral prisms; it is soluble with difficulty in hot water, insoluble in cold water. The salt decomposes at 235°-236°.

The aurochloride—C₅H₁₄N₂2HCl2AuCl (Au = 50·41 per cent.), melting-point 188°—crystallises partly in cubes and partly in needles, and is easily soluble in water.

Other salts are the picrate, C₅H₁₄N₂2C₆H₂(NO₂)₃OH, melting-point 221° with decomposition; with difficulty soluble in cold, but dissolving in hot water, and insoluble in absolute alcohol. There are also a neutral oxalate, C₅H₁₄N₂,H₂C₂O₄ + 2H₂O, melting-point 160°; and an acid oxalate, C₅H₁₄N₂2H₂C₂O₄ + H₂O, melting-point 143° with decomposition; both these oxalates are insoluble in absolute alcohol.

Cadaverine dibenzoyl—C₅H₁₀(NHCOC₆H₅)₂, melting-point 129°-130°—crystallises in needles and plates, soluble in alcohol and slightly soluble in ether, insoluble in water.

It is not acted on by hot dilute acids or alkalis, and when dissolved in concentrated hydrochloric acid and alcohol it is, only after prolonged boiling, decomposed into benzoic acid and the free base. The benzoic acid after getting rid of the alcohol by evaporation, can be removed by shaking up with ether; then the hydrochloride can be decomposed by an alkali and the free base obtained, or the platinum salt of cadaverine may be formed by precipitation with platinum chloride. Should cadaverine and putrescine be in the same liquid, the dibenzoyl compounds may be separated as follows:—the crystalline precipitate is collected on a filter, washed with water until the filtrate runs clear, and then dissolved in warm alcohol; this solution is poured into twenty times its volume of ether and allowed to stand; after a short time crystals form of the putrescine compound, which are far less soluble in alcohol than those of cadaverine dibenzoyl; these crystals are filtered off and repeatedly crystallised from alcohol until the melting-point is about 175°-176°. The filtrate contains the cadaverine compound; this latter is recovered by evaporating off the ether-alcohol.

§ 665. Putrescine—Tetramethylenediamine, C₄H₁₂N₂=NH₂CH₂CH₂CH₂CH₂NH₂.

The free base is a clear liquid, with a semen-like odour, boiling-point 135°. It is a common base in putrefying animal substances, and also occurs in the urine in cases of cystinuria. It can be obtained synthetically by reducing ethylene cyanide by the action of sodium in absolute alcohol.

The best method of separating putrescine is the benzoyl chloride method already given.

Putrescine forms crystalline salts, of which the following are the most important:—

Putrescine hydrochloride, C₄H₁₂N₂2HCl, forms long colourless needles, insoluble in absolute alcohol, easily soluble in water.

The platinochloride, C₄H₁₂N₂2HCl.PtCl₄ (Pt = 39·2 per cent.), is with difficulty soluble in cold water. When pure, the salt is in the form of six-sided plates.

The aurochloride, C₄H₁₂N₂2HCl.2AuCl₃ + 2H₂O (Au = 51·3 per cent.), is insoluble in cold water, in contradistinction to cadaverine aurochloride, which easily dissolves.

The picrate, C₄H₁₂N₂2C₆H₂(NO₂)₃OH, is a salt of difficult solubility. It crystallises in yellow plates. It browns at 230°, and melts with evolution of gas at 250°.

Dibenzoylputrescine, C₄H₈(NHCOC₆H₅)₂, forms silky plates or long needles, melting-point 175°-176°. By boiling it for twelve hours with alcohol and strong hydrochloric acid the compound may be broken up into hydrochloride of putrescine and free benzoic acid. As stated before, it is less soluble in alcohol than the corresponding compound of cadaverine.

Putrescine is not poisonous. On the other hand, by repeated treatment with methyl iodide, it takes up four methyl radicals, and the tetramethyl compound, C₄H₈(CH₃)₄N₂, produces symptoms similar to those of muscarine poisoning.

§ 666. Metaphenylenediamine,

, is a crystalline substance, melting-point 63°, boiling-point 276°-277°. The crystals are easily soluble in alcohol or ether, with difficulty in water. The least trace of nitrous acid strikes a yellow colour from the formation of triamidobenzol.

§ 667. Paraphenylenediamine,

, is in the form of tabular crystals, melting-point 140°, boiling-point 267°. If this substance is oxidised with ferric chloride or manganese binoxide and sulphuric acid, chinone is produced; if treated with SH₂ and ferric chloride, a violet sulphur-holding colouring matter, allied to methylene blue, is formed; these reactions are tests for the presence of the para-compound.

Both these diamines are poisonous. Metaphenylenediamine produces, in the dog, the symptoms of an aggravated influenza with continual sneezing and hoarse cough, which, if the dose is large enough, ends in coma and death. Paraphenylenediamine produces exophthalmia, the tissues of the eye undergoing complete alteration.[663]

[663] Comptes Rend., cvii. 533-535.

Both compounds, in doses of 100 mgrms. per kilo., cause more or less salivation, with diarrhœa. The para-compound is more poisonous than the meta-compound. So far as the author is aware, neither of these diamines have been separated with certainty from the urine of sick persons, nor from products of decomposition.

§ 668. Hexamethylenediamine, C₆H₁₆N₂.—Hexamethylenediamine has been found by A. Garcia [664] in a putrefying mixture of horse-flesh and pancreas.

[664] Zeit. f. physiol. Chemie, xvii. 543-555.

§ 669. Diethylenediamine, C₄H₁₀N₂, is a crystalline substance, melting-point 104°, boiling-point 145°-146°. After melting, it solidifies on cooling, forming a hard crystalline mass. It is extremely soluble in water, and is deposited from alcohol in large transparent crystals. A technical product called “spermin piperazidin” or “piperazine” has been found by A. W. v. Hoffmann [665] to be identical with diethylenediamine. The hydrochloride crystallises in colourless needles, insoluble in alcohol, readily soluble in water. The platinochloride, C₄H₁₀N₂H₂PtCl₆, is in small yellow needles, and is fairly easily soluble in hot water, but dissolves but slightly in hot alcohol. The mercuro-chloride, C₄H₁₀N₂H₂HgCl₄, crystallises in concentrically grouped needles, and is readily soluble in hot water, but is reprecipitated on adding alcohol. The picrate, C₄H₁₀N₂,C₆H₂(NO₂)₃OH, crystallises from water in yellow needles, almost insoluble in alcohol.[666]

[665] Ber., xxiii. 3297-3303.

[666] Sieber, J., Ber., xxiii. 326-327.

§ 670. Mydaleine is a poisonous base discovered by Brieger in putrid animal matters. It is probably a diamine, but has not been obtained in sufficient quantity for accurate chemical study. The platinochloride is extremely soluble in water, and only comes down from an absolute alcohol solution. It has been obtained in a crystalline form, giving on analysis 38·74 per cent. of platinum, C. 10·83 per cent., H. 3·23 per cent.

Mydaleine is very poisonous. Small quantities injected into guinea-pigs cause dilatation of the pupil, an abundant secretion from the nose and eyes, and a rise of temperature. Fifty mgrms. cause death. The post-mortem appearances are not distinctive; the heart is arrested in diastole; the intestines and bladder are contracted. In cats it causes profuse diarrhœa and vomiting.

§ 671. Guanidine.—Guanidine may be considered to have a relation to urea; for, if the oxygen of urea is replaced by the imide group NH, guanidine originates thus:—

Hence guanidine from its structural formula is a carbodiamidimide. Guanidine may be formed by the action of oxidising agents, such as potassic chlorate and hydrochloric acid, on guanine; or by heating amide cyanide with ammonium chloride, and so forming guanidine chloride. It is also produced from the oxidation of albumin. When boiled with baryta-water it decomposes into urea and ammonia. It combines with acids to form salts; the gold salt, CH₅N₃HCl,AuCl₃, is in the form of long yellow needles, with difficulty soluble in water. Guanidine nitrate, CH₅N₃HNO₃, is also almost insoluble in cold water and similar to urea nitrate. By dissolving equivalent parts of phenol and guanidine in hot alcohol, triphenylguanidine is formed; on adding picric acid to a solution of triphenylguanidine, phenylguanidine picrate, CH₂Ph₃N₃C₆H₂(NO₂)₃OH, is formed, and falls as a precipitate of slender needles, melting-point 208°; this picrate is very slightly soluble, 1 part dissolving in 12,220 parts of water at 15°. Guanidine is poisonous.[667]

[667] O. Prelinger, Monatsb., xiii. 97-100.

A method of separating guanidine from urine has been worked out by Gergers and Baumann.[668] The principle of the method is based upon the fact that guanidine is precipitated by mercurous oxide. The urine is precipitated by hydrate of baryta, the precipitate filtered off, the alkaline filtrate neutralised by hydrochloric acid, and the neutral filtrate evaporated to a syrup on the water-bath; the syrup is exhausted by absolute alcohol, and the alcoholic solution filtered; this filtrate is freed from alcohol by distillation, the alcohol-free residue dissolved in a little water, shaken up with freshly precipitated mercury oxide, and allowed to stand for two days in a warm place; the precipitate formed is collected, acidulated with HCl and treated with SH₂; the mercury sulphide thus obtained is separated by filtration, the filtrate evaporated, and the residue dissolved in absolute alcohol. This solution is precipitated by platinum chloride, filtered, separated from any platinum ammonium salt, and evaporated to a small volume. After long standing the guanidine salt crystallises out. The best method to identify it appears to be, to ascertain the absence of ammonia and of urea, and then to gently warm the supposed guanidine with an alkali, which breaks guanidine up into ammonia and urea, according to the following equation:—

NH=C(NH₂)₂ + H₂O = NH₃ + CO(NH₂)₂.

[668] Pflüger’s Archiv, xii. 205.

The physiological effects of guanidine are as follows:—

A centigrm. of guanidine salt injected into the lymph sac in the back of frogs produces, after a few minutes, muscular convulsions: first, there are fibrillar twitchings of the muscles of the back; next, these spread generally so that the whole surface of the frog seems to be in a wave-like motion. Irritation of the limbs produces tetanus. There is, at the same time, increased secretion from the skin. The breathing is irregular. In large doses there is paralysis and death. The heart is found arrested in diastole. The fatal dose for a frog is 50 mgrms.; but 1 mgrm. will produce symptoms of illness. In dogs there is paralysis, convulsions, vomiting, and difficult breathing.

§ 672. Methylguanidine,

.—Methylguanidine has been isolated by Brieger from putrefying horse-flesh; it has also been found in impure cultures in beef broth of Finkler and Prior’s Vibrio proteus. Bocklisch isolated it, working with Brieger’s process, from the mercuric chloride precipitate, after removal of the mercury and concentration of the filtrate, by adding a solution of sodium picrate. The precipitate contained the picrates of cadaverine, creatinine, and methylguanidine; cadaverine picrate, insoluble in boiling absolute alcohol, was separated by filtering from a solution of the picrates of the bases in boiling absolute alcohol; the alcohol was evaporated from the filtrate and the residue taken up with water. From this aqueous solution the picric acid was removed and then the solution precipitated with gold chloride; methylguanidine was precipitated, while creatinine remained in solution.

Methylguanidine aurochloride, C₂H₇N₃HCl.AuCl₃ (Au = 47·7 per cent.), forms rhombic crystals easily soluble in alcohol and ether; melting-point 198°. The hydrochloride, C₂H₇N₃HCl, crystallises in needles insoluble in alcohol. The picrate, C₂H₇N₃C₆H₂(NO₂)₃OH, comes down at first as a resinous mass, but, after boiling in water, is found to be in the form of needles soluble in hot absolute alcohol; melting-point 192°. The symptoms produced by methylguanidine are rapid respiration, dilatation of the pupils, paralysis, and death, preceded by convulsions. The heart is found arrested in diastole.

§ 673. Saprine, C₅H₁₄N₂.—Saprine is isomeric with cadaverine and neuridine; it was found by Brieger in human livers and spleens after three weeks’ putrefaction. Saprine occurs, in Brieger’s process, in the mercury precipitate. Its reactions are very similar to those of cadaverine; the main difference being that cadaverine hydrochloride gives a crystalline aurochloride, saprine does not; the platinum salt is also more soluble in water than the cadaverine salt. It is not poisonous.

§ 674. The Choline Group.—The choline group consists of choline, neurine, betaine, and muscarine.

All these bodies can be prepared from choline; their relationship to choline can be readily gathered from the following structural formulæ:—


Choline.	Neurine.	Betaine.	Muscarine.

Choline is a syrup with an alkaline reaction. On boiling with water, it decomposes into glycol and trimethylamine. It gives, when oxidised, muscarine. It forms salts. The hydrochloride is soluble in water and absolute alcohol; neurine hydrochloride and betaine hydrochloride are but little soluble in absolute alcohol, therefore this property can be utilised for their separation from choline. The platinochloride is insoluble in absolute alcohol; it melts at 225° with effervescence, and contains 31·6 per cent. of platinum. The mercurochloride is soluble with difficulty even in hot water. The aurochloride (Au = 44·5 per cent.) is crystalline, and with difficulty soluble in cold water; but is soluble in hot water and in alcohol; melting-point 264° with decomposition.

Choline is only poisonous in large doses.

§ 675. Neurine (Trimethyl-vinyl-ammonium hydrate), C₂H₃N(CH₃)₃OH.—Neurine is one of the products of decomposition of choline. It is poisonous, and has been separated by Brieger and others from decomposing animal matters. In Brieger’s process, neurine, if present, will be for the most part in the mercuric chloride precipitate, and some portion will also be in the filtrate. The mercury precipitate is decomposed by SH₂, the mercury sulphide filtered off, and the filtrate, concentrated, treated with absolute alcohol and then precipitated by platinum chloride. It is usually accompanied by choline; the platinochloride of choline is readily soluble in water, neurine platinochloride is soluble with difficulty; this property is taken advantage of, and the platinochloride crystallised from water until pure. Neurine has a strong alkaline reaction.

Neurine chloride, C₅H₁₂N.Cl, crystallises in fine needles. The platinochloride, (C₅H₁₂NCl)₂PtCl₄ (Pt = 33·6 per cent.), crystallises in octahedra. The salt is soluble with difficulty in hot water.

The aurochloride, C₅H₁₂NClAuCl₃ (Au = 46·37 per cent.), forms flat prisms, which, according to Brieger, are soluble with difficulty in hot water.

Neurine is intensely poisonous, the symptoms being similar to those produced by muscarine.

Atropine is an antidote to neurine, relieving in suitable doses the effects, and even rendering animals temporarily immune against the toxic action of neurine.

When a fatal dose of neurine is injected into a frog there is in a short time paralysis of the extremities. The respiration stops first, and afterwards the heart, the latter in diastole.

The symptoms in rabbits are profuse nasal secretion and salivation with paralysis, as in frogs. Applied to the eye, neurine causes contraction of the pupil; to a less degree the same effect is produced by the ingestion of neurine.

Trimethyloxyammonium hydrochloride causes similar symptoms to neurine, but the action is less powerful.—V. Cervello, Arch. Ital. Biol., vii. 232-233.

§ 676. Betaine.—Betaine may be separated from a solution in alcohol as large deliquescent crystals; the reaction of the crystals is neutral. Distilled with potash, trimethylamine and other bases are formed.

Betaine chloride, C₅H₁₂NO₂Cl, forms plates permanent in the air and insoluble in absolute alcohol. A solution of the chloride in water gives, with potassium mercuric iodide, a light yellow or whitish yellow precipitate, soluble in excess; but, on rubbing the sides of the tube with a glass rod, the oily precipitate crystallises as yellow needles; probably this is characteristic.

The aurochloride (Au = 43·1 percent.) forms fine cholesterine plates, soluble in water; melting-point 209°. Betaine is not poisonous.

§ 677. Peptotoxine.—Brieger submitted to the action of fresh gastric juice moist fibrin for twenty-four hours at blood heat. The liquid was evaporated to a syrup and boiled with ethylic alcohol, the ethylic alcohol was evaporated, the residue digested with amylic alcohol, and the amyl alcohol in its turn evaporated to dryness; the residue was a brown amorphous mass that was poisonous. It was farther purified by treating the extract with neutral lead acetate and then filtered; the filtrate was freed from lead by SH₂ and treated with ether, the ethereal extract being then separated and evaporated to dryness; this last residue was taken up with amyl alcohol, the alcohol evaporated to dryness, and the residue finally taken up with water and filtered. The filtrate is poisonous. The poisonous substance, to which Brieger gave the provisional name of peptotoxine, is a very stable substance, resisting the action of a boiling temperature, and even the action of strong alkalies. It gives precipitates with alkaloidal group reagents, and strikes a blue colour with ferric chloride and ferricyanide of potassium. The most characteristic test seems to be its action with Millon’s reagent (a solution of mercury nitrate in nitric acid containing nitrous acid); this gives a white precipitate which, on boiling, becomes intensely red.

It is poisonous, killing rabbits in doses of 0·5 grm. per kilogrm., with symptoms of paralysis and coma. The nature of this substance requires further elucidation.

§ 678. Pyridine Alkaloid from the Cuttle Fish.—O. de Coninck [669] has obtained, by Gautier’s process, an alkaloid from the cuttle fish, of the formula C₈H₁₁N, in the form of a yellow, mobile, strongly odorous liquid, very soluble in alcohol, ether, and acetone, boiling-point 202°. It quickly absorbs moisture from the air. It forms two mercuric chlorides, one of which has the formula (C₈H₁₁N,HCl)₂HgCl₂; this compound crystallises in small white needles, slightly soluble in water and dilute alcohol, but insoluble in absolute alcohol, and decomposing when exposed to moist air. The other salt is a sesqui-salt, forming long yellowish needles, insoluble in ordinary solvents, and decomposing when exposed to moist air. The alkaloid also forms deliquescent very soluble salts with hydrochloric and hydrobromic acids. A platinum salt is also formed, (C₈H₁₁N)₂H₂PtCl₆; it is of a deep yellow colour, almost insoluble in cold, but soluble in hot water; it is decomposed by boiling water, with the formation of a very insoluble compound in the shape of a brown powder, (C₈H₁₁N)₂PtCl₄. Coninck’s alkaloid, on oxidation with potassic permanganate, yields a gummy acid; this acid, on purifying it by conversion into a potassium salt and then into a cupric salt, was found to be nicotinic acid; so that the alkaloid is undoubtedly a pyridine compound; indeed, the acid, distilled with lime, yields pyridine.

[669] Comptes Rend., cvi. 858, 861; cviii. 58-59, 809-810; cvi. 1604-1605.

§ 679. Poisons connected with Tetanus.—Brieger, in 1887, isolated a base of unknown composition, to which he gave the name of “spasmotoxine.” It was produced in cultures of the tetanus bacillus in beef broth.

Two more definite substances have also been discovered, viz., tetanine and tetanotoxine.

Tetanine, C₁₃H₃₀N₂O₄, is best isolated by the method of Kitasato and Weyl.[670] Their method of treating broth cultures of the tetanus bacillus is as follows:—

[670] Zeit. f. Hygiene, viii. 404.

The broth is digested with 0·25 per cent. HCl for some hours at 460°, then rendered feebly alkaline, and distilled in a vacuum. The residue in the retort is then worked up for tetanine by Brieger’s method; the distillate contains tetanotoxine, ammonia, indol, hydrogen sulphide, phenol, and butyric acid. On treating the contents of the retort by Brieger’s mercury chloride method, the filtrate contains most of the poison. The mercury is removed by SH₂, the filtered solution evaporated and exhausted by absolute alcohol, in which the tetanine dissolves. Any ammonium chloride is thus separated, ammonium chloride being insoluble in absolute alcohol. The alcoholic solution, filtered from any insoluble substance, is next treated with an alcoholic solution of platinum chloride, which precipitates creatinine (and any ammonium salts), but does not precipitate tetanine. The platinum salt of tetanine may, however, be precipitated by the addition of ether to the alcoholic solution. The platinum salt, as obtained by precipitation from ether, is very deliquescent; it has, therefore, to be rapidly filtered off and dried in a vacuum. It can then be recrystallised from hot 96 per cent. alcohol, forming clear yellow plates; these plates, if dried in a vacuum, become with difficulty soluble in water.

Tetanine may be obtained as a free base by treating the hydrochloride with freshly precipitated moist silver oxide. It forms a strongly alkaline yellow syrup, and is easily decomposed in acid solution, but is permanent in alkaline solutions.

The platinochloride, as before observed, is precipitable by ether from alcoholic solution; it contains 28·3 per cent. of platinum, and decomposes at 197°.

The base produces tetanus.

§ 680. Tetanotoxine may be distilled, and be found in the distillate with other matters. It forms an easily soluble gold salt, melting-point 130°. The platinochloride is soluble with difficulty, and decomposes at 240°. The hydrochloride is soluble in alcohol and in water, melting-point about 205°.

Tetanotoxine produces tremor, then paralysis, and lastly, violent convulsions.

§ 681. Mydatoxine, C₆H₁₃NO₂.—A base obtained by Brieger from horse-flesh in a putrefactive condition and other substances. It is found in the mercury chloride precipitate. The free base is an alkaline syrup, isomeric with the base separated by Brieger from tetanus cultures. The hydrochloride is a deliquescent syrup, not forming any compound with gold chloride, but uniting with phospho-molybdic acid in forming a compound crystallising in cubes. It forms a double salt with gold chloride, sparingly soluble in water. The platinochloride (Pt = 29 per cent.) is very soluble in water, but not soluble in alcohol; melting-point 193° with decomposition.

The base in large doses is poisonous, causing lachrymation, diarrhœa, and convulsions.

§ 682. Mytilotoxine, C₆H₁₅NO₂.—This is believed to be the poison of mussels. Brieger isolated it as follows:—

The mussels were boiled with water acidified by hydrochloric acid; the liquid was filtered, and the filtrate evaporated to a syrup, and the syrup was repeatedly extracted with alcohol. It was found advisable to exhaust thoroughly with alcohol, otherwise much poison remained behind. The alcoholic solution was treated with an alcoholic solution of lead acetate. The filtrate was evaporated and the residue extracted with alcohol. The lead was removed by SH₂, the alcohol distilled off, water added to the remaining syrup, and the solution decolorised by boiling with animal charcoal. The solution was neutralised by sodium carbonate, acidulated with nitric acid, and precipitated with phosphomolybdic acid. The precipitate was then decomposed by warming with a neutral solution of lead acetate, and the filtrate (after the removal of the lead by the action of SH₂) was acidulated with HCl and evaporated to dryness. The residue was then extracted with absolute alcohol, filtered from any insoluble chloride, e.g., betaine chloride, and precipitated by mercury chloride in alcohol.

The free base has a most peculiar odour, which disappears on exposure to air; at the same time, the poisonous properties also diminish. The base is destroyed by boiling with sodium carbonate; on the other hand, the hydrochloride may be evaporated to dryness or be boiled without decomposing.

The hydrochloride crystallises in tetrahedra; the aurochloride crystallises in cubes (Au=41·66 per cent.). Its melting-point is 182°.

§ 683. Tyrotoxicon (Diazobenzol, C₆H₅N₂(OH)).—It appears, from the researches of Vaughan and others, that diazobenzol is liable to be formed in milk and milk products, especially in summer time. It is confidently asserted by many that the summer diarrhœa of infants is due to this toxine; however that may be, it is well established that diazobenzol is a violent poison, causing sickness, diarrhœa, and, in large doses, an acute malady scarcely distinguishable from cholera, and which may end fatally. There will always be difficulty in detecting it, because of its instability. The following is the best process of extraction from milk. The milk will probably be acid from decomposition; if so, the whey must be separated by dilution and filtration; without dilution it may be found impracticable to get a clear filtrate. In order to keep the bulk down, 25 c.c. of the milk may be diluted up to 100 c.c., and, having obtained a clear filtrate from this 25 c.c. thus diluted, the filtrate is used to dilute another 25 c.c. of milk and so on. The acid filtrate is neutralised by sodium carbonate, agitated with an equal volume of ether, allowed to stand in a stoppered vessel for twenty-four hours, and the ether then separated and allowed to evaporate spontaneously. The residue is acidified with nitric acid and then treated with a saturated solution of potash, which forms a stable compound with diazobenzol, and the whole concentrated on the water-bath. On cooling, the tyrotoxicon compound forms six-sided plates. Before the whole of this process is undertaken, it is well to make a preliminary test of the milk as follows:—A little of the ether is allowed to evaporate spontaneously. Place on a porcelain slab two or three drops of a mixture of equal parts of sulphuric and carbolic acids, and add a few drops of the aqueous solution; if tyrotoxicon be present, a yellow to orange-red colour is produced. A similar colour is also produced by nitrates or nitrites, which are not likely to be present under the circumstances, milk having mere traces only of nitrates or nitrites; it may also be due to butyric acid, which, in a decomposed milk, may frequently be in solution. Therefore, if a colour occurs, this is not absolutely conclusive; if, however, no colour is produced, then it is certain that no diazobenzol has been separated. That is all that can be said, for the process itself is faulty, and only separates a fractional part of the whole.

§ 684. Toxines of Hog Cholera.—Toxines have been isolated by F. G. Novy [671] from a cultivation of Salmon’s bacillus in pork broth. The fluid possessed a strong alkaline reaction. For the isolation, Brieger’s method was used. The mercury chloride precipitate was amorphous and was converted into a chlorine-free platinum compound, to which was assigned the composition of C₈H₁₄N₄PtO₈. After separation of this compound, the mother liquor still contained a platinum salt crystallising in needles, and from this was obtained the chlorhydrate of a new base, to which was given the name of susotoxine; it had the composition of C₁₀H₂₆N₂2HCl,PtCl₄. Susotoxine gives general alkaloidal reactions, and is very poisonous.

[671] Med. News, September 1890.

§ 685. Other Ptomaines.—Besides the ptomaines which have been already described, there are a number of others; the following may be mentioned: isoamylamine,[672] (CH₃)₂CH.CH₂.CH₂NH₂; butylamine, CH₃CH₂CH₂CH₂NH₂; dihydrolutidine,[673] C₇H₁₁N; hydrocollidine,[674] C₈H₁₃N; C₁₀H₁₅N (a base isolated by Guareschi and Mosso [675] from ox-fibrin in a state of putrefaction by Gautier’s method; it forms a crystalline hydrochloride and an insoluble platinochloride; its action is like that of curare but weaker); aselline,[676] C₂₅H₃₂N₄, isolated from cod-liver oil; typhotoxine,[677] C₇H₁₇NO₂, isolated from cultures of Eberth’s bacillus. So far as the published researches go, it would appear that other crystalline substances have been isolated from the urine, from the tissues, and from the secretions of patients suffering from various diseases; the quantity obtained in each case has, however, been, under the most favourable circumstances, less than a gramme; often only a few milligrms. To specifically declare that a few milligrms. of a substance is a new body, requires immense experience and great skill; and, even where those qualifications are present, this is too often impossible. This being so, the long list of named ptomaines, such as erysipeline, varioline, and others, must have their existence more fully confirmed by more than one observer before they can be accepted as separate entities.

[672] Hesse, Chem. Jahresb., 1857, 403.

[673] Gautier, A., and Morgues, Compt. Rend., 1888.

[674] Gautier et Etard, Bull. Soc. Chim., xxxvii., 1882.

[675] Guareschi et Mosso, Les ptomaines, 1883.

[676] Gautier, A., et Morgues, Compt. Rend., 1888.

[677] Brieger, 1885, Ptomaines, iii.