a green colour with quinine, red with narceine, and orange with narcotine, &c.

11. Many alkaloids may be identified by the temperature at which they sublime, and the microscopic character of the sublimate.

12. Many others are best identified by their physiological action, e.g. convulsions produced by strychnine, the peculiar taste sensations produced by aconitine, &c.

The occurrence and importance of alkaloidal substances in the animal body were first brought into prominence by a murder trial in Rome, in which a servant was accused of poisoning his master with the alkaloid delphinine. The accused was acquitted because the alkaloid obtained from the corpse, though giving many of the reactions of delphinine, differed from delphinine in certain other reactions of which the most important was its action on the frog's heart; delphinine brings the frog's heart to a standstill in diastole; the alkaloid obtained from the corpse stopped the heart in systole. The question was then taken up by a number of Italian investigators, of whom the most prominent was Francesco Selmi of Bologna. This investigator obtained from corpses which had undergone putrefactive changes, and also from various kinds of putrefying proteid (albumin, peptone, casein, &c.), a number of alkaloidal substances closely resembling the vegetable alkaloids both in reactions and physiological effects. He found some which, like atropine, dilated the pupil and accelerated the heart; others, like morphine, muscarine, strychnia, &c., in their physiological effects, and also in some of their chemical reactions and colour tests.

After Selmi's discoveries, other murder trials brought into prominence the subject of the cadaveric alkaloids in other countries; in London a criminal named Lamson was accused of murdering a young man with aconitine; the defence unsuccessfully set up was that the alkaloid found in the body of his victim was not a vegetable alkaloid at all, but one of the ptomaines produced by putrefactive processes after death.

The subject, however, has not merely a medico-legal interest, for it has been demonstrated that alkaloids exist in different forms of putrefying food.

In Germany sausages made with bad meat have been known to produce epidemics of a serious disorder, which we now know have been produced by these cadaveric alkaloids.

Certain forms of stale milk and cheese have caused more or less widespread outbreaks of serious morbid symptoms in those who have

consumed these articles of diet. A ptomaine named tyrotoxicon by Dr. Vaughan has been separated from bad cheese.

Poisoning by mussels and other forms of shell fish is also due to the presence in them of an animal alkaloid (mytilotoxine).

Of equal importance and interest to the physician are the poisons produced by bacteria in different forms of disease. Schmidt,2 Panum,3 and others separated from septic fluids a substance which was called sepsin; it was found to correspond closely in its reactions to the alkaloids; this was, however, before the general importance of the ptomaines was fully recognised. On injecting this material into the circulation, symptoms resembling those of septicemia were produced. The conclusion was drawn, and probably correctly drawn, that this material was the substance produced by bacteria in ordinary septic processes, and that it is the real toxic agent in cases of blood-poisoning. Since then other ptomaines have been separated by more exact methods from pure cultivations of certain pathogenic bacteria, notably two named putrescine and cadaverine by Brieger; these are especially abundant in cultivations of Koch's comma or cholera bacillus ; substances similar to these are probably the true chemical poisons in cholera. There is still a large field open to investigators in this direction, but enough has been given in the way of instances to indicate the overwhelming importance of the subject to the pathologist. These ptomaines, then, are produced from animal substances by the influence of bacteria. The next questions which arise are, from what are the ptomaines formed, and how do the bacteria produce them? One of the most important of the ptomaines is neurine; this is a decomposition product of lecithin and doubtless arises from the lecithin contained in nerve, muscle, blood, and other parts of the body after death; also in eggs, milk, and cheese, and other forms of food. It is, however, fully proved that ordinary proteids will also, under the influence of certain bacterial growths, produce neurine, putrescine, cadaverine, as well as the simpler bases, such as methylamine, ethylamine, and ammonia. The question, how the bacteria do it is a more difficult matter to answer. The decomposition of lecithin produced by these organised ferments is no doubt similar to that brought about by ordinary chemical reagents; but we cannot describe the decomposition of proteids until we know their composition. The different views now held as to the constitution

Zeit. physiol. Chem. x. 146.

2 Inaug. Diss. Dorpat, 1869.

3 Virchow's Archiv, 1863, vol. xxvii. p. 240; vols. xxviii. xxix. and others. 4 The probability that cholera is caused by an alkaloid was first pointed out by Lauder Brunton (Brit. Ass. Reports, 1873); he deduced it from the similarity of the symptoms of cholera and alkaloid (muscarine) poisoning. Cadaverine and putrescine are not markedly toxic.

of a proteid will each involve a separate theory as to how an alkaloid may be formed from it. It may, however, be regarded as settled that animal alkaloids, whether of the ptomaine or leucomaine series, are produced anaerobically (see p. 164).

2

The priority of describing an alkaloidal substance in animals is claimed by Dupré and Bence Jones. These observers in the year 1866 described an alkaloidal substance, which they separated from the solid and liquid tissues of animals, and they named it Animal Quinoidine.' 1 The honour is also claimed for a chemist who worked at Stettin, named Marquardt, who described an alkaloid obtained from a corpse, to which he gave the name 'septicin,' and which he found was similar in its action to coniine. The work of Panum, Schmiedeberg, Bergmann, and Schmidt on sepsin has been already alluded to. These were all more or less gropings in the dark until the master hand of Selmi3 placed the matter on a satisfactory basis; it was he, too, who invented the word 'ptomaine.' The details of methods of separation and of analysis have, as usual, been left to a multitude of German workers, but Brieger stands head and shoulders above all the rest. In France the subject has been taken up by Gautier, who has produced numerous memoirs on the subject.1

Brieger was the first to obtain from the uncrystallisable extracts and syrupy products of previous investigators pure materials in a crystalline form. He found it necessary to adopt considerable modifications of the Stas-Otto process, which is the best for the extraction of the vegetable alkaloids. The pure crystalline alkaloids were not only analysed by him, but in many cases their constitution was worked out also. He found that the bases isolated from putrefactive mixtures were less poisonous than those produced by pathogenic bacteria. These latter poisons include such substances as typhotoxine (from cases of typhoid fever), tetanine" (from cases of tetanus), and several others; on account of their powerful poisonous properties Brieger has separated them from the other ptomaines, and calls them toxines.

It has been recognised that it is very difficult to draw the limits of the word ptomaine; the products of metabolism of bacteria are not, in general, different from those of the higher organisms; thus choline, neurine, creatinine, &c., are normal products occurring in, or separable from, healthy animal tissues. Gautier has invented the word leucomaine

1 Proc. Roy. Soc. xv. 73. Zeit. f. Chem. 1866, p. 348.

? Schuchardt in Maschka's Handb. d. ger. Med. ii. 60.

3 Deutsch. chem. Gesell. xi. 808.

4 For the latest see Bull. Soc. Chim. xi. 6.

For the last paper on tetanine from a case of tetanus, see Brieger, Berlin. klin. Wochenschrift, 1888, No. 17.

for the basic products produced in the tissues of living animals by metabolic processes, while he reserves the word ptomaine for those formed by putrefaction after death. It must, however, be remembered that many leucomaines are powerful poisons.

If ptomaines and leucomaines are to include all bases produced in animals, the simpler substances, like methylamine, trimethylamine, &c., must all come under either one or the other heading. This is especially necessary, since it has been shown that probably the diamines, like putrescine and cadaverine,2 are derived by oxidation from the monamines.3

Such, then, is a sketch of the ptomaines, in which their importance has been indicated by a few examples. The subject is yet in its infancy, and many more facts must be collected before positive general conclusions can be drawn. Without at all wishing to minimise their importance, it is, however, necessary to insist on one point, and that is that all poisons produced by bacteria are not necessarily ptomaines, that all mysterious symptoms in obscure complaints cannot be as yet attributed to leucomaines.

There is always a tendency after any great discovery is made to We have attribute to it wider importance than it really possesses. many instances of this in pathology: the doctrine of the solidists, which totally excluded humoralism, was an outgrowth of Schwann's great generalisation we call the cell theory. Similarly there can be little doubt that under the influence of the germ theory many premature conclusions were jumped at, concerning the association of organisms with disease. Ptomaines are now displacing somewhat the microbe, which was formerly regarded as all-important, but this must not be pushed too far. The discovery of ptomaines is complemental, not antagonistic, 1 Putrescine (C4H12N2) is chemically tetramethylenediamine (Ber. deutsch. chem. Gesell. xxi. 2938).

2 Cadaverine (C5H14N2) is pentamethylenediamine (Ladenburg, Ibid. xix. 2585). Two other alkaloids named neuridine and saprine have been separated by Brieger, which are isomeric with cadaverine.

3 A full explanation will be found in an interesting paper by Baumann and v. Udranszky (Zeit. physiol. Chem. xiii. 562). These observers show that the two diamines which are found in cholera, and in pure cultivations of the cholera bacillus, are also found in the urine and fæces of patients suffering from cystinuria, a condition apparently very different from cholera. Normal urine is toxic, but this is probably due to the inorganic potassium salts in it (Stadthagen, Zeit. klin. Med. xv. parts 5 and 6), not to any alkaloid. Ptomaines have never (until these cases of cystinuria were described) been satisfactorily demonstrated to exist either in normal or pathological urine, though theoretically their presence there is possible, for the ptomaines formed by putrefaction in the intestine might conceivably be partly reabsorbed and then excreted in the urine. Ponchet (Compt. rend. xcviii. 1560) has stated that normal urines contain poisonous alkaloids; his methods and results are, however, full of fallacies. Hunter has found diamines in the urine in cases of pernicious anæmia.

to the germ theory. We must remember that there are many powerful poisons which are not alkaloids at all. Snake poison is a striking example of this; it is a poisonous proteid indistinguishable from other proteids by its reactions. The products of digestion produced normally in the alimentary canal (albumoses and peptones) are also powerful poisons. Recently it has been surmised that the bacillus anthracis produces a poisonous albumose, which also has the power of conferring subsequent immunity from the attacks of the bacillus.1 Not doubt the poisonous proteids, as well as the ptomaines, will have to be very largely reckoned with in the investigations of the poisons of diseases.

METHODS OF SEPARATION OF PTOMAINES

The first method of any importance for the separation of alkaloids from organic mixtures was proposed by Stas, subsequently modified by Otto,3 and now known as the Stas-Otto process. Other methods have been introduced by Dragendorff, Sonnenschein, Selmi, and Brieger." The last-named observer's process is specially adapted for the separation of ptomaines.

The Stas-Otto process.”—The substance to be operated on, if solid, is finely divided, and repeatedly digested for many hours with fresh quantities of rectified spirit at a temperature of 55° C. Liquids are also treated with twice their volume of spirit. The residue is finally digested at 35° C. with spirit faintly acidified with acetic acid; it is then once or twice more digested with unacidified spirit. The alcoholic liquids obtained before acidification are mixed together, and rapidly and momentarily raised to 70° C., cooled, and filtered; those obtained with and after the use of acetic acid are mixed together and similarly treated. But the two liquids, the unacidified and the acidified, are not mixed with one another till later. Each infusion is then concentrated to a syrupy consistency at a temperature of 35° C. To the syrup about 30 c.c. of absolute alcohol are added, with constant stirring and grinding in a mortar. The alcohol is poured off from the pasty mass, and replaced by successive portions of 15 c.c. of alcohol, so long as a colour is imparted to it. The alcoholic extracts are mixed, filtered, and the filtrate concentrated as before at 35° C. We have again a syrupy residue, both from the unacidified and the acidified original extracts; each is diluted with water, filtered, and the filtrates mixed. They should now measure 15-20 c.c. This is partially neutralised with soda, but, still faintly acid, is placed into a wellstoppered tube. This liquid contains all the alkaloids present in the original material, and is free from proteids. This aqueous liquid (A) is now covered with twice its volume of ether, and the whole is mixed by gently and repeatedly inverting the tube. The ether is allowed to separate, and is pipetted off. A fresh quantity of ether is then used, and the extraction with ether repeated until a few drops on evaporation leave no residue; four or five extractions generally suffice. Each ethereal solution is washed by shaking it with 5 c.c. of water to

1 See p. 168.

5 Otto, Ibid. c. 39.

2 Stas, Liebig's Annalen, lxxxiv. 379.

4 Dragendorff, Gerichtl. chem. Ermit. v. Gift, 1876.

3 Sonnenschein, Liebig's Ann. cv. 45.

Selmi, Journ. of Chem. Society, 1877, p. 93.

'Brieger, Die Ptomaïne, part i. 1885; part ii. 1885; part iii. 1886.

As modified by Dr. Stevenson, Watts' Dict. vol. i. 1888. Art. 'Alkaloids poisonous."