This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
The value of phosphorus in conditions of extreme exhaustion in advanced disease is one of the earliest recorded experiences of Kramer, Mentz, Leroy, etc. (1733-1798). They used it in the muttering delirium and incipient coma of typhus, the collapse of malignant "bilious fever," and the profound depression of extensive pneumonia. Bayle says, "in every disease where death is imminent from failure of vital force without much structural alteration, phosphorus is indicated. We see this in severe continuous fevers during their last stage, whether they be caused by some miasm, typhus, plague, etc., or by ' spontaneous alteration of the blood,' as in adynamic or putrid fevers (so called); in such cases phosphorus reanimates vitality, furnishes nature the means of effectually resisting the disease, and eliminating its material causes by natural excretory outlets. It is indicated, secondly, in all acute exanthemata when eruption has disappeared suddenly, with aggravation of symptoms (measles, variola, erysipelas, low fever with exanthem); thirdly, in malignant pustule, where the disease has reached its acme and the vital power is almost extinct." Bayle adds that it is useful in chronic gout and rheumatism (which are relieved through profuse excretion of sweat or urine), and "all morbid conditions wherein it is proper to excite these secretions, and at the same time to stimulate vitality in a speedy and energetic manner" ("Bibliotheque de Therapeutique," vol, ii.).
Powers so extensive as these have not been accorded to phosphorus by more modern writers, but Mr. Clay has illustrated its value in the collapse of variola (Lancet, ii., 1858, p. 315), and Dr. John Brunton in the adynamia of typhus and typhoid fevers, rapid improvement taking place under drachm-doses of the following solution: Tinct. phosph. aeth. (gr. 1/3 ad 3 j.) 3 iij., Spt. vini rectif. 3 ss., Glycerini ad 3 iss. About two grains were taken in the course of two days.
I have frequently prescribed phosphorus in the exhaustion of typhus and typhoid, and have sometimes seen remarkably good results from it; but, on the other hand, have been often disappointed, and cannot but consider it an uncertain remedy in such cases. I would place more dependence upon ammonia, camphor, and other stimulants of that class, but, if they failed, should then have recourse to phosphorus. Another use of the drug in fevers is to assist development of the specific eruption, e.g., in enteric, scarlet fever, and measles, and within my own experience it has proved of service when the eruption has disappeared suddenly with the onset of serious symptoms.