The poisonous symptoms caused by the heavy metals are discussed in their respective chapters, and, as the subject does not permit of accurate wide generalisations, the reader is referred to the various special articles. See ARSENIC, COPPER, IRON, LEAD, and PHOSPHORUS ; also OCCUPATION DISEASES.
The aromatic hydrocarbons, as they are known in chemistry, constitute still another important group of poisons. The most important of these is carbolic acid, and associated with this as to action are the innumerable compounds, which, when taken into the body and broken dovm, form in the tissues substances resembling carbolic acid. The number of these is legion. The most important, however, are such preparations as creolin, cresol, creosol, benzol, guaiacol, resorcin, pyrocatechin, hydroquinone, salicylic acid and the salicylates, oil of wintergreen, tar, lvsol, etc.
Most of these compounds have a local action, of an acute irritating nature, causing burning, or being caustic and destructive ; and. on absorption into the body, they have an action on the blood similar to that already mentioned as causing metluemoglobin, so that the symptoms resulting are a combination of the local irritating effects at the point of application as well as at the point of elimination, notably with the kidney, and with the blood itself, as already noticed. A more detailed account of the symptoms caused by this class of poisons will be found in the section. on CARBOLIC ACID.
The substances known as toxalbumins constitute a peculiar group of acute poisons. To this class belong the poison found in the seeds of the castor-oil bean (ricinin), a similar substance found in the seed of the wild liquorice (abrin), the mushroom poison (phallin), the poisons of various snakes (notably the rattlesnake, the copperhead, and the cobra), and a number of bacterial poisons, particularly the toxins of the typhoid-bacillus and the diphtheria-bacillus, etc.
This is an intensely interesting class of poisons, the knowledge concerning which is of comparatively recent acquisition. Such is the condition of knowledge concerning this group that it is impossible to characterise it as yet. These poisons are termed globulins, and, so far as is now known, the destructive action which they cause is limited to the blood. They have a peculiar property of being able to dissolve the blood-cells in the body, and hence are known as haemolytic substances. This action is not unknown in some other poisons, for members of the phenol group (carbolic acid), when given in enormous doses, can produce similar blood destructions. But this group of toxalbumins is unique in its very destructive effect on the blood-cells. This renders it extremely difficult to treat patients poisoned by these substances, and their effect can be modified only by means of true specific antidotes which will prevent the destructive action. Some of these counteracting substances have been discussed in the section on IMMUNITY.
POLLUTIONS.—Sce SEMINAL. LOSSES.
POMEGRANATE.—The rind of the fruit, or the bark of the stem and root, of Punica granatum, or pomegranate, a tree of the myrtle family. This drug has a specific action on tapeworms. This is due to the presence of two alkaloids, pelletierin and isopelletierin. Pelletierin is most com monly used, and is combined with tannic acid. The dose is from ten to twenty grains. An overdose may cause nausea and vomiting, giddiness, confusion, and marked weakness. Vision may be dimmed, or entirely lost temporarily.