Klebs23 even claims that he has found the infectious agent—a monas pulmonale—which can be inoculated, with the result of developing croupous pneumonia. This has been credited so far as to lead to the subcutaneous injection of carbolic acid to destroy the pneumonic germ. Incidentally, it may be remarked that it has been shown that the contagion of the pleuro-pneumonia of cattle, according to Parkes, "has been found in the pus- and epithelium-cells of the sputa." The true nature of the pneumonia poison, if one exists, is as little determined as that of the other acute contagious general diseases. But, whatever its nature may be, its primary action seems to be on the nerve-centres.
23 Arch. für exper. Path. u. Pharm., vol. iv., 1875.
SYMPTOMS.—The symptoms of croupous pneumonia may be considered under two heads—Subjective, or rational symptoms; and Objective, or physical signs.
Subjective Symptoms.—In only a small proportion of cases are there prodromata. Grisolle found that prodromata occurred in 50 out of 205 adult cases, or in about 25 per cent.; and Fox says that he finds the proportion to be about 28 per cent. In old age they seem to be more frequent, the proportion being about 60 per cent.24
24 Durand-Fardel, Mal. des Viellards.
There may be for a day or two, or even for a week, preceding a pneumonic seizure a feeling of general malaise, accompanied by anorexia, headache, dull pains in the limbs, back, and lumbar region, vertigo, epistaxis, or slight diarrhoea. Sometimes the skin assumes a slightly jaundiced hue, and there may be flashes of heat accompanied by, or alternating with, slight rigors. Flying pains in the limbs and chest and epistaxis are common in senile croupous pneumonia. When prodromes have existed more than three or four days, they will be vague and undefined.
Rise in temperature as a prodrome is by some thought to be caused by a deep-seated and undiscoverable hepatization. But let us take one example from many in support of a contrary view—viz. the case of an inmate of Bellevue Hospital during the winter of 1880–81. For three days preceding the first appearance of consolidation the temperature ranged at 102° and 103° F. During this time there were several slight rigors followed by flashes of heat.
Wilson Fox25 states that he knows of but one case—the one referred to by Monthus in his Essai sur la Pneumonie double.
25 Reynolds's System, art. "Pneumonia."
In epidemics febrile symptoms and diarrhoea often precede for some two or three days the first sign of consolidation.26