Phosphorus is insoluble in water, but soluble in ether, chloroform, and the oils. It is readily oxidized to phosphorous acid, which is an inert compound. It resembles arsenic in its action, but is less irritant locally, and has a greater tendency to produce fatty degenerations. Charteris (1903), in his studies on the bone-marrow, administered it subcutaneously to rabbits. In the early stages the marrow showed hyperemia and an increase in the leukoblastic tissue; after prolonged administration the marrow was markedly degenerated. In growing animals the growth of bone has been decidedly promoted, the cancellous portion giving way to the development of hard bone. In adult animals Charteris found no change in the bones.

Toxicology

Acute poisoning somewhat resembles that from arsenic. After a latent period, which may be several hours, there are burning in the stomach, abdominal pain, and vomiting. At first the liver is swollen, but it soon undergoes a rapid atrophy of the type of acute yellow atrophy. Jaundice usually comes on in twenty-four hours. There are leucin, tyrosin, and other incompletely oxidized bodies in the urine. The local antidote is an oxidizing agent, such as peroxide of hydrogen or potassium permanganate. Scoville says that old turpentine oil changes the phosphorus into a non-toxic turpentine-phosphorous acid. Other oils should not be employed unless promptly washed from the stomach.

Chronic poisoning is to be seen among the makers of matches, Its chief manifestation is "fossy jaw," a condition of necrosis of the jaw bones which is incurable, and often necessitates extensive curetage of the parts to check the horrible cadaverous odor. It may even require removal of the entire maxilla. Charteris laid bare the periosteum of the lower jaw of rabbits, and repeatedly exposed them to phosphorus fumes, but could not get necrosis.

Therapeutics

Phosphorus has been used in dose of 1/100 grain (0.0006 gm.) in the treatment of rickets and osteomalacia. It is given in the form of a pill, an elixir, or a 1 per cent, solution in olive oil. It is probably mostly inert.

The hypo phosphites (Na2Po2, CaPo2, etc.) have been much employed as nerve tonics. The belief that they furnish phosphorus to the nerve tissues is negatived by the fact that they pass unchanged through the system, and can be almost entirely recovered from the urine as hypophosphites. The compound syrup of the hypophosphites contains the hypophosphites of calcium, potassium, and sodium; dose, 2 drams (8 c.c.).

The Glycerophosphates

Calcium Glycerophosphate, Capo4

C3H5(OH)2, is soluble in 50 parts of water at 25° F. ( - 4o C.) and more soluble at lower temperatures; the sodium salt, Na2Po4.-C3H5(OH)2, is very soluble in water and is deliquescent. Dose of each, 4 grains (0.24 gm.) They are esters of phosphoric acid, and their administration results in an increase in the urinary phosphates. They are at the present time much in use as general "nerve tonics" and have largely replaced the useless hypophosphites. But there is no satisfactory evidence that they increase the phosphorus in the nervous tissues, or that in exhaustion the nervous tissues are lacking in phosphorus; and there is abundant evidence that the body can get its needed phosphorus quite as well from the inorganic phosphates; at least this is the case in hens and ducks, which give out a large amount of phosphorus in their eggs in the form of lecithin. Fingerling tried to enrich the milk of goats by the administration of phosphorus compounds. He found that, even when the food was deficient in phosphorus, the organic phosphorus compounds exerted no more favorable influence than the inorganic ones. Marshall (1915) corroborates this finding.

Lecithin (see page 32) is a glycerophosphoric acid, substituted by two fatty acid radicals, and combined with choline. It contains about 4 per cent. of phosphorus, and probably sets free phosphoric acid. It occurs in most animal and plant cells, but especially in the brain and nerves, yolk of egg, fish-eggs, blood-plasma, and bile. An ordinary mixed diet may furnish as much as 1 to 2 drams (4-8 gm.) per day (von Noorden). It is broken up by the pancreatic juice into glycerophosphoric acid, fatty acids, and choline (Dixon). When used in the emulsification of fats it promotes their absorption.

It is "a very important material for building up the complicated phosphorized nuclein substances of the cell and cell nucleus" (Hammarsten). Its administration in large amounts in anemia tends to increase the hemoglobin and red cells and to improve the nutrition. Nerking, by the injection of a lecithin-saline solution in rabbits, was able to cut short or abolish anesthesia and narcosis. He looked upon this as evidence in favor of the Meyer-Overton theory of narcosis.

When eggs are available it hardly seems of advantage to prescribe the commercial lecithin in doses of 5 to 10 grains (0.3-0.7 gm.).