Phosphorus is present in varying proportions in food - meat, milk, eggs, cheese, and animal foods generally being richer in this ingredient than vegetable foods. Except, however, in young growing animals it is hardly possible to conceive of there being a deficiency of this substance in any reasonable mixed diet. A deposit of phosphorus in the urine is not of infrequent occurrence in quite ordinary circumstances, but it is only when urine heavily laden with calcium and magnesium phosphates issues in a turbid milky condition from the bladder that the term "phos-phaturia" is requisitioned to describe it. This does not necessarily indicate either an active increase of these substances in the urine or the existence of any morbid process whatever, but is dependent either upon a relative increase of the alkalis or a relative decrease of acids in the urine.

The most common occasion for the appearance of such a deposition of phosphates is a diminution in the acidity of the urine, due to a diet rich in alkaline carbonates, or one containing alkaline salts of vegetable acids or alkaline albuminates, because these yield alkaline carbonates after being consumed in the body. This results in a transformation of the soluble diacid phosphates into insoluble monacid or insoluble normal phosphates. A temporary retention of acid in the body, as after a meal especially rich in protein, is often followed in two or three hours by excretion of insoluble phosphates, simply because there is for the nonce a relative increase of the alkali in the urine. The condition is hence sometimes termed anaciduria, and it is to be observed likewise after the body sustains a distinct loss of acid, e.g., from vomiting, especially in hyperchlorhydria or after repeated washing out of the stomach.

To effect a disappearance of the phosphatic urinary deposit, it is not always necessary to resort to the exhibition of acids, but it is much wiser, especially in neurasthenic cases, to enjoin hygienic and tonic treatment. When, as is sometimes the case, an acid is indicated, then, as Hutchison has shown, the preference should be given to acid sodium phosphate.

A special form of phosphaturia, associated with excess of lime in the urine and a corresponding diminution of calcium in the faeces, has been described in children, and owes its existence to an alteration in the secretion of the mucous membrane of the large intestine, usually referred to colitis. It is practically the only form really amenable to dietetic treatment, the deposit quickly disappearing after the substitution of an acalcic diet for one rich in lime. Excess of phosphorus pentoxide over calcium in the food is stated to be the cause of a very prevalent bone disease amongst the horses, mules, and donkeys of South Africa, for when the oat-hay and maize, which show a preponderance of the acid compound over the basic one, and which constitute the ordinary diet of these animals, are supplemented by lucerne or other leguminous fodder, rich in lime, the disease rapidly disappears.

Joulie asserts that the blood is an acid fluid because it retains in solution calcium and magnesium phosphate, both of which are precipitated in alkaline or even feebly acid solutions. He has evolved a process for estimating - what he terms - the "physiological" acidity of the urine, which he considers an index to the acidity of the blood. By comparing this with the P2O5 content of the urine he obtains data which enable him to state whether hypophosphatia or hyperphosphatia exists, a valuable indication for treatment.

A considerable amount of evidence has been advanced in recent years in support of the belief that beri-beri - a disease the outstanding characteristic of which is multiple peripheral neuritis - really owes its origin to a deficiency of the organic compounds of phosphorus. It has long been known that tropical beri-beri occurs with great frequency in certain Eastern races where the staple diet is rice, and in a general way the incidence of the disease has been associated with polished rice, from which the outer layers, including the pericarp, had been removed in milling. Ship beri-beri arises among the European crews of sailing ships who have been deprived for long periods of fresh food, and have been compelled to live on dry food, especially peas and beans, which could only be softened by prolonged boiling in soda, and pickled meat so old that it had parted with much of its organic phosphorus.

It has been conclusively demonstrated by Schaumann amongst others that rice capable of inducing tropical or ship beri-beri would also produce polyneuritis in fowls which were fed exclusively upon it, and that even barley and white wheat flour, in which the outer layers of the grains have been removed in milling, and in which consequently the proportion of phosphorus is very low, could induce the same disease. Identical results were produced by removal of the organic phosphorus from food-stuffs by the action of the solvents or its destruction by a high temperature.

Now, while the addition of inorganic or organic phosphates in no way nullifies the deleterious action of the defective food-stuff, it is a fact of pregnant import that substances rich in organic compounds of phosphorus, such as pancreas, peas or beans, yeast, testicular extracts, or wheat bran and rice meal - the parts of the rice and wheat removed in milling - are by being added to the food capable of preventing the development of the disease in animals or curing it when present. It is essential, however, that these articles should be used to supplement the food in sufficient quantities to supply at least 2 grams of phosphorus per day, that being the minimum amount required for an adult. It is also known that oatmeal, rye bread, whole rice (paddy), and barley, all of which contain organic compounds of phosphorus in varying degree, are incapable of setting up polyneuritis in pigeons, and that beri-beri does not occur when rice containing a sufficiency of P2O5, "cured rice," is used.

Edie and Simpson, who subjected the matter to the test of experiment, have published their results, so far at least as they relate to wheat. They found that adult pigeons fed exclusively on unadulterated and unbleached white wheat bread rapidly developed polyneuritis and died on the average on the twenty-ninth day. They rapidly revived, however, on the addition of yeast to the diet, provided this was not delayed too long, and on an exclusive diet of wholemeal or standard bread, which contains 80 per cent, of the wheat berry, they maintained proper health.

It is evident therefore that the organic compounds of phosphorus are absolutely essential to the health and well-being of man, and that he is unable to manufacture his own organic compounds of phosphorus from inorganic phosphorus.

It is even probable that a daily supply of the different compounds of organic phosphorus is necessary, as no proof exists to show that nucleins, lecithins, phosphatides, phytins, or other varieties, are capable of being substitutes the one for the other.