Organs of Respiration and Circulation. 607 



lung, which the cut b discloses to be referable to effusion into its 

 substance. 



The exudation of the altered liquor sanguinis is not limited 

 to the lungs themselves, but extends to their investing mem- 

 brane, the pleura, thus accounting for the depositions of semi- 

 solid fibrine on their exterior, and the existence of serous effusions 

 in the cavity of the thorax. That these results are not pro- 

 duced by inflammation is clear from the circumstance that in 

 innumerable cases no redness of either the pleura covering the 

 lungs or lining the chest can be detected; both the fibrine and 

 the serum being likewise perfectly colourless. Dropsy of the 

 chest may be said to be now associated with dropsy of the lungs. 

 Although inflammation takes no part in the original production 

 of these morbid lesions, still, as previously remarked, it may arise 

 as a consequence, and this I believe is generally the case with 

 those animals which recover. The blocking up of the air-cells, 

 vessels, Sec, produces death of these structures; and when this is 

 partial and of little extent, portions of the lung will ultimately 

 become detached, and be enclosed in sacs formed by the adhesive 

 stage of the subsequent inflammation. This will also explain 

 how it is that collections of pus and other morbid products are 

 occasionally met with in our post-mortem examinations of long- 

 existing cases of pleuro-pneumonia. It ought therefore to be no 

 matter of surprise, nor to be viewed as an opprobrium of the vete- 

 rinary art, that an affection which depends on an empoisoned 

 atmosphere, and is associated with such extensive lesions of organs 

 so essential to health, and which stealthily but securely wends its 

 way and saps the very vitals, should prove so destructive to life, 

 and likewise resist the most vigorous and scientific treatment. 



Having given my view of the nature of the malady, I proceed 

 to narrate the symptoms which accompany it. The disturbance 

 of the animal's health is rarely observed until the disease is fully 

 established, and effusion into the lung has made some progress. 

 Proprietors of cattle should, therefore, be early and late with 

 their stock, narrowly watching the slightest indication of ill-health. 

 It will often be observed that oxen at pasture, when the dis- 

 ease is commencing, will early in the morning be separated from 

 the herd, standing under the hedge with their backs arched, coats 

 staring, and refusing to eat; while as the day advances they will 

 join the rest and appear in their usual health. A slight but 

 husky cough will be occasionally recognised, and now and then 

 the breathing will be increased, as if the animal had under- 

 gone some extra exertion ; while in milch-cows there will be a 

 diminished amount of milk in addition to the above svmptoms. 

 As the disease progresses, the cough becomes more frequent and 

 husky, the respiration is hurried, the pulse increased and some- 



