This section is from the book "Our Dogs And Their Diseases", by G. S. Heatley. Also available from Amazon: Our Dogs and Their Diseases.
This disease may be confined to the parent tube, or it may extend to the ultimate ramifications of the smaller branches. There is an increased secretion of mucus collecting in the inferior parts of the tubes and plugging up the orifices, thus throwing the greater part of the lungs out of action. The changes, then, that occur, are, in the first stage the membrane is reddened owing to the increased vascularity, it then becomes dry, when it is termed congestion. Then exudation commences with the formation of lymph, this lymph becomes passive and mixed up with the pus, which again becomes mixed up with the secretions of the tubes, filling them and giving to the respired air a frothy-looking appearance. When the disease has arrived at this stage, we find congestion of the lungs, owing to the fact that the blood cannot get purified; therefore it remains stagnant in the capillaries or small vessels. In the favourable stage the exudation is taken up by the absorbents into the blood, then excreted by the various organs of the body as deleterious material; therefore it will often be observed, that when an animal is recovering from this and like affections, it passes an extraordinary quantity of water. Herein is witnessed an effort of nature to throw off from the system those poisonous ingredients which are foreign to a healthy organisation.
Bronchial mucous membrane almost black, that is, the lining membrane of all the tubes is in this condition. There is also a frothy purulent mucus present so thick that it can be drawn from the place on which it lies in strings, while congestion of the lungs is beautifully illustrated, and often inflammation.
When bronchitis terminates in recovery, it is by a softening of this lymph, which, as I have already stated, becomes absorbed. Man can amuse himself by spitting it up, which of course accelerates recovery, but not so with our patients; hence it is that a much longer time is required to effect a cure. The unfavourable signs are, pulse increasing in frequency and losing strength; the membrane of the nose becomes of a leaden hue, legs deathly cold, ears the same; excessive weakness, irregularity in the bowels, with secretion of urine defective.
The favourable symptoms are, pulse slower and stronger, cough getting looser, and breathing and lifting of the flanks not so great; the patient gets warmer about the extremities, and looks altogether more lively, with returning appetite and the natural excretions taking place.
Symptoms of bronchitis are invariably ushered in by a cough which is short, dry, and husky. It is dry because the mucous membrane is dry, but soon becomes hoarse and moist when exudation has set in. By-and-by it becomes rough and painful, then short and frequent, and if you place your ear to the patient's side, just behind the shoulder-blade, you will in the first stage hear a dry sound, but this soon changes into one that is hoarse and rattling, produced by the air becoming entangled in the mucus.
In a healthy animal you can hear the air passing into the lungs, but it comes out noiselessly, while in bronchitis the opposite is exactly the case. The respirations now become increased, the breathing gets shallow and short, with heavy lifting at the flanks. There is irritative fever, with the pulse soft, quick, and compressible. In the latter stages the ears and legs are cold, mouth dry and clammy, while the animal stands with its head and nose extended. There is not much dulness or pain in the chest, but there is early weakness, which is always the greatest when the disease is brought on by epizootic causes.
Bronchitis causes death by suspending the action of the lungs, or rendering them incapable of performing their functions, and this is termed asphyxia, or suffocation. The action of the lungs being arrested, the blood does not get purified; hence we find them congested, or, in other words, loaded with blood. We may have this congestion without the lungs being inflamed at all, but, as a rule, they are affected.
First, it is of great importance to place the dog in a cool, comfortable place, where the atmosphere is not too cold, and where you have security from draughts. If the patient is inclined to eat you must be very cautious, and feed sparingly, as the food in large quantities distends the abdomen, causing injury through pressure to the respiratory organs.
Great caution must be observed in the giving of medicines, as purgatives are intolerable. This is due to the mucous membranes of the bowels often participating with those of the lungs; therefore this warning ought to be remembered. Apply plenty of hot water, and if this cannot be procured, blister the sides with mustard made up with acetic acid, and administer extract of belladona, sweet spirits of nitre given in whisky or ale twice daily, and allow also nitre in the water to drink.
Should these instructions be carefully carried into execution, you may expect that your efforts will be rewarded by the animal's recovery in about a fortnight. But should the disease run on to pneumonia (or inflammation of the lungs), there is now little hope of a successful issue.
 
Continue to: