DISEASES OF THE LUNGS. 



The lungs, though very susceptible to disease, possess 

 comparatively little sensibility, either in health or disease. 

 They are peculiar to themselves, and are extremely varied 

 in structure. The bronchial tubes constitute one part;* 

 the air-cells, in which the tubes terminate, another ; their 

 blood vessels a third ; the inter-connecting parenchyma- 

 tous substance a fourth ; the cellular and pleural mem- 

 branes a fifth. In health they possess a pale pink, spongy, 

 light, and elastic interior, and will float in water. In 

 disease they are reddened and solidified (liver-like), and 

 sink in water. 



In horses diseases of the lungs are more numerous in 

 proportion to other diseases than in man. They are also 

 more rapid in their course, death sometimes resulting in 

 a few hours. Young horses are more subject to them 

 than old. High-bred, tenderly reared, light bodied, long 

 legged, flat sided, narrow breasted, and thin skinned 

 horses are more predisposed to them than those of the 

 opposite kind. The causes of them are chiefly foul air, 

 especially when combined with heat ; sudden changes of 

 temperature, dampness, overwork, and mechanical and 

 chemical injuries. (Percivall.) 



PNEUMONIA 



Means either congestion or inflammation of the lungs, 

 independent or combined. Inflammatory pneumonia is 

 either simple or compound. When complicated with bron- 

 chitis, it is called ' broncho-pneumonia ; ' when complica- 

 ted with pleurisy, 'pleuro-pneumonia/ Its progress will 



