PNEUMONIA.— INFLAMMATION OF THE LUNGS. 209 



stration, the ravages which disease occasionally commits in the very centre of the 

 rib-cased cavity of the body." 



A horse with any portion of the lungs hepatized cannot be sound. He cannot be 

 capable of continued extra exertion. His imperfect and mutilated lung cannot supply 

 the arterialized blood which long-continued and rapid progression requires, and that 

 portion whicii is compelled todo the work of the whole lung must be exposed to injury 

 and inflaminuliou from many a cause that would otherwise be harmless. 



Another consequence of inflammation of the substance of the lungs is the formation 

 of tubercles. A greater or smaller number of distinct cysts are formed — cells into 

 which some fluid is poured in the progress of inflammation : these vary in size from 

 a pin's point to a large egg. By degrees the fluid becomes concrete ; and so it con- 

 tinues for a wliile — the consequence and the source of inflammation. It occupies a 

 space that should be employed in the function of respiration, and by its pressure it 

 irritates the neighbouring j)arts, and exposes them to inflammation. 



By and by, however, another process, never sufficiently explained, commences. 

 The tubercle l)egins to soften at its centre, — a process of suppuration is set up, and 

 proceeds until the contents of the cyst become again fluid, but of a diflferent character, 

 for they now consist of pus. The pus increases; the cyst becomes more and more 

 distended; it encroaches on the substance of the lungs; it comes into contact with 

 other tubercles, and the walls opposed to each otlier are absorbed by their mutual 

 pressure ; they run together, and form one cyst, or regular excavation, and this some- 

 times proceeds until a considerable portion of the lung is, as it were, hollowed out. 

 By and by, however, the vomica presses upon some bronchial passage ; the cyst gives 

 way, and the purulent contents are poured into the bronchise, and got rid of by the 

 act of coughing. At other times the quantity is too great to be thus disposed of, and 

 the animal is suffocated. Occasionally it will break through the pleuritic covering 

 of the lung, and pour its contents into the thorax. 



Abscesses may exist in the lungs undiscovered It is scarcely conceivable to what 



extent they sometimes exist in animals of slow work, without being detected by the 

 usual means of examination, Mr. Hales says that he gave a physic-ball to a cart- 

 mare with a bad foot, and she soon afterwards died suddenly. When inquiring as to 

 the cause of death, he was told, and not very good-humouredly, that his physic had 

 killed her. He asked if it had purged her violently 1 " No !" it was replied, " it 

 had not operated at all." She was opened, and the mystery was all unravelled. 

 The tliorax was deluged with pus, and there were then in the lungs several large 

 abscesses, one of which contained at least a quart of pus. The mare had not shown 

 a symptom of chest affection, and the gentleman to whom she belonged declared that 

 he had believed her to be as sound as any horse he had in his possession. 



The resolution or gradual abatement of inflammation is the termination most to be 

 desired in this state of disease, for then the engorgement of the vessels will gradually 

 cease, and the thickening of the membrane and the interstitial deposit be taken up, 

 and the effusion into the cells likewise absorbed, and the lungs will gradually resume 

 their former cellular texture, yet not perfectly ; for there will be some induration, 

 slight but general ; or some more perfect induration of certain parts ; or the rupture 

 of some of the air-cells ; or an irritability of membrane predisposing to renewed inflam- 

 mation. The horse will not always be as useful as before ; there will be chronic 

 cough, thick wind, broken wind; but these merit distinct consideration; and, for the 

 present, we proceed to the treatment of pneumonia. 



There is inflammation of that organ through which all the blood in the frame passes 

 — that organ most of all subject to congestion. Then nothing can be so important as 

 to lessen the quantity of blood wliich the heart is endeavouring to force through the 

 minute vessels of the lungs, distended, irritated, breaking. Immediate recourse must 

 be had to the lancet, and the stream of blood must be suflTered to flow on until the 

 pulse falters, and the animal bears heavy upon the pail. This blood must be extracted 

 as quickly as possible, and the lancet should be broad-shouldered, and the orifice 

 large. This is the secret of treating inflammation of a vital organ. The disease is 

 weakened or destroyed, without permanently impairing the strength of the patient; 

 whereas, by small bleedings, and with a small stream, the strength of the patient is 

 sapped, while the disease remains untouched. 



Next comes purging, if we dared ; for by having recourse to it some cause of excite- 

 ment would be got rid of, the circulating fluid would be lessened, and a newdetenni- 

 18* 2b 



