The bronchi are filled with frothy, whitish mucus; the small bronchi sometimes contain fibrous concretions and the mucous membrane is injected, and may be destroyed in places. The bronchial lymphatic glands are enlarged, congested, and contain small hæmorrhages.
It is important in making a post-mortem examination to be able to distinguish pneumonia from peripneumonia. This is comparatively easy if one bears in mind that in the latter pleurisy always exists, that the interlobular connective tissue spaces are always greatly distended with a citrine-coloured serosity, that on section the peripneumonic lung resembles a mosaic; and that, finally, the course of hepatisation is centripetal, the inflammation commencing at the periphery of the lobule, and progressively extending towards the centre. In pneumonia, on the contrary, pleurisy is always absent; the interlobular connective spaces are only distended slightly, if at all, and always contain a brownish-red serosity: the course of hepatisation is centrifugal; it commences in the pulmonary alveoli, and extends towards the periphery and the interlobular divisions. The following table gives a résumé of the other differences between the two diseases:—
| Peripneumonia. | Pneumonia. |
|---|---|
| Œdema of the dewlap. | No œdema of the dewlap. |
| Pleural exudate. | No pleural exudate. |
| Centripetal lobular hepatisation. | Ascending centrifugal lobar hepatisation. |
| Extreme infiltration of the interlobular connective tissue spaces (primary yellow infiltration). | Moderate infiltration of the interlobular connective tissue spaces (secondary reddish-brown infiltration). |
Treatment. Good hygiene, regular ventilation, moderate warmth, and the administration of tepid drinks facilitate recovery.
Certain German authors recommend cold compresses to the thorax, douches, and cold enemata in pneumonia. We do not think that such treatment has proved very successful, although it has been well tried.
The classic treatment commences with moderate bleeding, the free application of mustard to the sides, the application of moxas, frictions with antimonial or blister ointment, and the administration of draughts containing 2 to 2½ drachms of tartar emetic per day, or considerable doses of alcohol; and this treatment seems to have given the best results. Antithermic agents, like acetanilide, phenacetin and quinine sulphate, are too costly to be greatly used in bovine medicine. Salicylate of soda is preferable.
In order to assist circulation, support the tone of the heart and avoid engorgement of the lung and asphyxia; digitalis should be given in doses of ¾ to 1 drachm per day, or digitalin in subcutaneous injections of 5 to 6 milligrammes, continued for five or six days. Finally, iodide of potassium may be given in doses of 1 to 1½ drachms, to reduce inflammation and as an expectorant.
PNEUMONIA DUE TO FOREIGN BODIES—MECHANICAL PNEUMONIA.
It may happen that in examining a patient pneumonia is diagnosed under circumstances which seem to forbid its being regarded as simple or primary. This may be explained by the fact that ruminants are very apt to suffer from pneumonia produced by foreign bodies. The lung may be penetrated either by some sharp object making its way forwards from the rumen or reticulum or by liquid or solid material passing into the trachea. These are two common methods by which this form of pneumonia is produced.