It may be noticed that the following differences exist between pneumonic and catarrhal sputa: catarrhal sputa contain 10 to 14 per cent. of alkaline earths; pneumonic sputa contain no alkaline phosphates. In catarrh the ratio of the soda to the potash is 31 to 20; in pneumonia the ratio is 15 to 41. There is 3 per cent. of sulphuric acid in catarrhal and 8 per cent. in pneumonic sputa.
Early in pneumonia there is an increase of the fixed salts, notably chloride of sodium, in the serum of the blood. It has been thought that from the rapid and excessive cell-transformation in the lung the chloride of sodium is attracted to that organ. In one case where no sodium chloride was found in the urine 10 per cent. of the solid material of the sputa consisted of that salt. Still, the presence of it in the sputa and blood, and its absence from the urine, are facts that still need elucidation.33
33 Beale gives the following analytical table of a case of acute pneumonia:
| Chloride of Sodium. | Per cent. of Solids. |
| Urine | 0.00 |
| Blood from heart | 0.68 |
| Hepatized lung | 2.59 |
| Healthy lung | 1.43 |
The expired air in croupous pneumonia is colder than normal, and, as in many acute general diseases, there is a diminution in the amount of carbonic acid excreted.
Temperature.—The temperature-range of a typical case of croupous pneumonia shows it to belong to the remittent or subremittent type of diseases rather than to the class of febrile disorders marked by a continuous pyrexia. In rare instances it is intermittent.
As in most acute general diseases which are ushered in by a distinct chill, the temperature rises rapidly during the chill. In two or three hours after the chill it may range from 102° to 105° F. After twenty-four hours it is subject to evening exacerbations and morning remissions, but the morning temperature is rarely more than 2° F. lower than the evening. Indeed, the difference in the subremittent type may amount to only ½° F., and in the remittent type to only 1° F. At midnight a second exacerbation may occur, but not so marked as that occurring early in the evening. Occasionally the remissions occur in the evening and the exacerbations in the morning.
| FIG. 33. |
| A Typical Case of Lobar Pneumonia in the Adult: Recovery by Crisis. |
The temperature is usually highest on the evening of the third day. In some cases the maximum range may not be reached until a few hours before the crisis, on the fifth or sixth day. In fatal cases, just preceding death, the temperature may reach 107° or even 109° F.