Medical Jurisprudence, Volume 2 (of 3)

by John Ayrton Paris; J. S. M. Fonblanque

A CLASSIFICATION OF THE DIFFERENT MODES BY WHICH POISONS PRODUCE THEIR EFFECTS.

† This mark denotes that the substance, against which it is placed, may also act by being absorbed.

‡ Signifies that the article has also a local action.

I. BY ACTING THROUGH THE MEDIUM OF THE NERVES, WITHOUT BEING ABSORBED, AND WITHOUT EXCITING ANY LOCAL INFLAMMATION.

a. By which the functions of the nervous system are destroyed.

Acrid.

Aconite.

Jatropa Curcas.

Narcotico-Acrid.

Alcohol.

Oil of Tobacco.

Narcotic.

Essential Oil of Almonds.†

Camphor.†

Opium†?

b. By rendering the heart insensible to the stimulus of the blood.

Infusion of Tobacco.

Upas Antiar.

II. BY ENTERING THE CIRCULATION, AND ACTING THROUGH THAT MEDIUM WITH DIFFERENT DEGREES OF FORCE, ON THE HEART, BRAIN, AND ALIMENTARY CANAL.

Corrosive.

Arsenic.

Emetic Tartar.

Muriate of Baryta.

Acrid.

Hellebore.

Savine.

Meadow Saffron.

Squill.

Narcotic.

Opium.‡

Lettuce.

Henbane.

Prussic acid.

Narcotico-Acrid.

Deadly Nightshade.‡

Hemlock.

Camphor.‡

Cocculus Indicus.

III. BY A LOCAL ACTION ON THE MUCOUS MEMBRANE OF THE STOMACH, EXCITING A HIGH DEGREE OF INFLAMMATION.

Corrosive.

Corrosive Sublimate.†

Verdegris.

Muriate and

Oxide of Tin.

Sulphate of Zinc.

Nitrate of Silver.

Acids.

Alkalies.

Cantharides.†

Acrid.

Bryony.

Elaterium.†

Colocynth.†

Camboge.

Euphorbium.

Hedge Hyssop.

Croton Tiglium.

Ranunculi.

The preceding classification of poisons will not only furnish the practitioner with a general theorem for the administration of antidotes, but it will suggest the different modes and forms of administration of which each particular substance is susceptible; it will shew, that certain poisons may occasion death without coming into contact with any part of the alimentary canal, and that others will produce little or no effect, however extensively they may be applied to an external surface. The first class comprehends such poisons as operate, through the medium of the nerves, upon the organs immediately subservient to life; in the application of such agents it is obvious that they cannot require to be introduced into the stomach, they may convey their destructive influence by an application to any part duly supplied with nerves, and whose extremities are exposed to their action; although at the same time, it may be observed that, in general, poisons of this kind act most powerfully when internally administered, owing to the extensive sympathetic relations of this central organ over every function of the living body. The second class consists of poisons that are incapable of producing any effect, except through the medium of the circulation; whence we shall be enabled to explain and appreciate the various circumstances which may accelerate or retard their operation. Poisons of this class may be applied externally to abraded parts, or even to surfaces covered with cuticle, provided their absorption be promoted by friction; and it may be here observed, that the function of absorption is not performed with the same force in every tissue; as a general proposition it may be said to be energetic in proportion to the number of lymphatics and veins, although the late experiments of M. Majendie have shewn how greatly it is influenced by the state of the circulation.[^[213]] If these poisons be administered internally, they find their way into the circulating current either through the branches of the thoracic duct, or those of the venæ portarum; when, as if by a species of election, each substance very frequently expends its venom upon some one particular system of organs. Many of the substances arranged under this second division, have moreover a local effect upon the structure with which they first come in contact; it is thus with Colocynth, and some other bodies; while on the contrary, several of those poisons which are distinguished for their local action, are subsequently absorbed, and are thus as it were enabled to ensure their work of destruction by a double mode of operation. We shall receive ample evidence of this truth, as we proceed in the history of particular poisons. The third class comprises such agents as inflict their vengeance upon the mucous membrane of the stomach, by actual contact, and destroy, by exciting local inflammation.

MINERAL POISONS.

Under this head is included the greater proportion of those substances which are employed as the instruments of crime; for they are generally of easy access, require but little preparation, and are so destructive in small doses, and, at the same time, so little disgusting in flavour, as to furnish the assassin with the sure and secret means of destruction. Fortunately, however, for the ends of justice, such agents are pre-eminently the objects of successful analysis. In treating of the history of the individual substances derived from this kingdom, we shall consider, 1st. their external characters, such as form, colour, odour, taste, specific gravity; 2d. their chemical composition, and habitudes; 3d. the tests by which their presence may be recognised; 4th. the symptoms which they occasion; 5th. their physiological action; 6th. their different modes and forms of application; 7th. the lesions of structure they occasion; 8th. the phenomena presented on dissection.