Phosphorus, P,=31.

This non-metallic element was obtained in the seventeenth century from the urinary phosphates, by German chemists, and by Dr. Boyle in this country. London was, for some time, the principal place of its manufacture, so that it became known as "phosphorus anglicanus." It occurs, variously combined, in certain especially fertile soils, in the seeds of vegetables, and in the nerve-tissue and bone of animals (particularly when young), as well as in the blood and the urine.

Preparation

It is now procured from bone-ash (os ustum) by digesting it in sulphuric acid, and then distilling with charcoal.

The contained phosphate of lime is partially changed into superphosphate and metaphosphate: phosphorus distils over, and, by a further process of purifying, is obtained as a colorless, oily liquid, which solidifies in cakes, or in rounded hollow pencils, according to the shape of the glass moulds employed. The last part of the process may be represented thus: 3Ca(P03)2 +10C=4P+Ca3 (P04)2 + l0Co.

Characters

The cakes or pencils are colorless, waxy, and translucent when fresh, but on exposure become coated with an opaque layer of crystals, which may be white, yellowish, or sometimes red from the formation of an allotropic variety of phosphorus. Phosphorus inflames so easily that it needs to be kept under cold water, in which it is practically insoluble; in ether, turpentine, and oils it is soluble to a great extent; in rectified spirit it is but slightly so (1 part in 320); in chloroform, 1 per cent.; but in bisulphide of carbon it is wholly soluble. ("Fenian fire" is the term given to a very inflammable solution in this liquid, containing 70 per cent.) Naunyn states that phosphorus is very slightly soluble in water at 96° to 104° F.; it is more soluble in organic fluids. The element is soft and flexible at ordinary temperatures, melts at 110°, and takes fire at a little over that point; it is luminous in the dark, and, when exposed to air, gives off white vapors of phosphorous acid, exhaling an odor sui generis, which has been compared to that of garlic.

On exposure to sunlight or to heat in closed vessels, it is converted into red or "amorphous" phosphorus - a brittle powder which is not acted on by the air, and is insoluble; when volatilized, this reverts to the ordinary form.

Amorphous phosphorus has been, by some observers, credited with physiological activity. Thus, Bednar used it for a long period in small doses, and observed symptoms of excitation, trembling, and clonic convulsions; but as much as 1 oz. has been given to dogs without perceptible effect. Thompson, in twelve carefully observed cases, found its action nil, and plausibly attributes its supposed powers to a slight amount of contained ordinary phosphorus (Pharmaceutical Journal, July, 1875).

I believe it to be practically inert, and the following observations will refer only to the ordinary form.

Zinci Phosphidum - Phosphide of Zinc, PZn, (not officinal). A grayish, friable substance, having a lustrous, crystalline fracture, stable at ordinary temperatures, readily decomposed by weak acids, almost tasteless, but possessing active properties like those of phosphorus.

Absorption And Elimination

Phosphorus taken by the mouth, and especially when finely divided or dissolved, is absorbed into the blood under the influence of alkaline, albuminoid, or oleaginous materials with which it meets in the stomach and intestine; the amount and the rapidity of its absorption are proportionate to the amount of such materials, and especially of fats, which are its best solvents. The exact condition in which it circulates is still a subject for discussion; according to varying circumstances some portion may pass into the blood unaltered (Orfila, etc.), another oxidized, as hypophosphorous, phosphorous, or phosphoric acid (Frerichs, Munk and Leyden, etc.), and a third portion as phosphuretted hydrogen (Lecorche: Archives de Physiologie, 1-2). It has been found in each of these forms in certain cases of poisoning, though in other cases none at all has been detected.

Portions of unabsorbed phosphorus pass sometimes with the fa?ces, rendering them phosphorescent, and the urine has presented a similar appearance: the element has also been found in a free state in the liver, ten hours after death (Dybkowsky); it is eliminated by it, and by the other glandular organs, by the skin, and by the lungs.

Physiological Action (External)

When applied in substance, phosphorus has been known to inflame on the skin, and, indeed, has been used as a moxa; it is liable to cause very troublesome sores and even gangrene, and the same results may follow its use in ointment. In certain experiments on dogs, however, when pieces of the element were placed in the cellular tissue they remained unaltered as to size and trans-lucency, and no inflammation was excited, yet the animals are said to have died in a few weeks from phosphorus-poisoning; while, on the other hand, rabbits and some other animals treated in the same way did not show either local or general symptoms. Trasbot records a curious circumstance: a dog swallowed a stick of phosphorus, and no symptoms of local irritation appeared, and afterward it was found in an abscess as an ordinary foreign body might have been. It is not easy to draw definite conclusions from such experiments, other than that pure phosphorus does not necessarily act as a local irritant (Ranvier: Gazette Medicale, 1867; Archives Generales, 1868). Phosphorus vapor causes irritation, catarrh, and even inflammation of mucous membranes with which it comes in contact, especially the conjunctival and respiratory membranes; it has also a special effect in causing inflammation of the periosteum and bone, with necrosis of exposed parts, such as the maxilla and teeth. It is only when the phosphorus vapor directly reaches the periosteum or some raw vascular surface in immediate connection with the nutrition of bone, and when its application is prolonged under particular circumstances of temperature, and probably of oxidation, that its injurious effects are witnessed. Thus it is, when there are carious teeth in the jaw, and the fumes can act directly on the exposed dental pulp, that necrosis occurs, and it is noteworthy that not until eleven years after the opening of the match factory in Vienna was the first case of this kind seen, and only those engaged in "dipping and drying" the matches were affected. The disease is more common in the lower jaw, but not rare in the upper, and it has also attacked the palate and frontal bones. The general health of the workers previous to the necrosis or buccal inflammation is, with the exception of pulmonary catarrh, remarkably good.