296 THICK WIND. 



laborious. The changes of structure which accompany these states of 

 morbid respiration are as opposite as can be imagined. Induration of the 

 substance of the lungs, diminution of the number or the caliber of the 

 air-passages, are the causes of thich-wliid. If the portion of lung employed 

 is lessened, or the bronchial tubes will not admit so much air, the quick 

 succession of efforts must make up for the diminished effect produced hy 

 each. In hrolien-wind there is rupture of the air-cells, and an unnatural 

 intercommunication between them in the same lobule, or between those of 

 the neighbouring lobuli. The structure of the lung, and the discharge of 

 function, and the treatment too, being so diiferent, these diseases require 

 separate consideration. 



THICK-WIND. 



When treating of pneumonia, it was observed, that not only are the 

 vessels which ramify over the delicate membrane of the air-cells gorged 

 Ax-ith blood, but they are sometimes ruptured, and the cells are filled with 

 blood. The black, softened, pulpy appearance of the lungs thus produced, 

 is the rottenness of the groom and farrier, proving equally the intensity of 

 the inflammation and that it is of recent date. If the horse is not speedily 

 destroyed by this lesion of the substance of the lungs, the serous portion 

 of the effused blood is absorbed, and the solid becomes organised. The 

 cells are obliterated, and the lung is hepatlsed, — its structure bears consi- 

 derable resemblance to that of the liver. This may occur in patches, or it 

 may involve a considerable portion of the lung. 



• If a portion of the lung is thus rendered impervious, the remainder ^vill 

 have additional work to perform. The same quantity of blood must be 

 supplied with air ; and if the Avorking part of the machine is diminished, 

 it must move mth greater velocity as well as force — the respiration 

 must be quicker and more laborious. This quick and laboured breathing 

 can be detected even when the animal is at rest, and it is indicated 

 plainly eno.ugh by his sad distress when he is urged to unusual or con- 

 tinued speed. The inspirations and the expirations are shorter as well as 

 more violent — the air must be more rapidly admitted and more thoroughly 

 pressed out, and this is accompanied by a peculiar sound that can rarely 

 be mistaken. 



We may guess at the commencement of the evil by the laborious heav- 

 ing of the flanks, but by auscultation alone can we ascertain its progi'ess. 

 The increase of the crepitus will tell us that the miscliief is beginning, and 

 the cessation of the murmui* will clearly mark out its extent. 



The inflammatory stage of the disease having passed, and comparative 

 health being restored, and some return to usefulness having been estab- 

 lished, — the horse being now thicJc-winded, auscultation will be far more 

 valuable than is generally imagined. It will faithfully indicate the 

 quantity of hepatisation, and so give a clue to the degTee of usefulness, or 

 the extent to which we may tax the respiratory system ; and it will also 

 sei-ve to distinguish, and that very clearly, between the cause of tliicli- 

 ^oiiid, and the morbid changes that may have resulted from bronchitis, or 

 thickening of the parietes of the air-passages, and not the obliteration of 

 the air-cells. 



Of the Treatment little can be said. We know not by Avhat means we 

 can excite the absorbents to take up the solid organised mass of hepatisa- 

 tion, or restore the membrane of the cells and the minute vessels ramify- 

 ing over them, now confounded and lost. We have a somewhat better 

 chance, and yet not much, in removing the thickening of the membrane ; 

 for counter-irritants, extensively and perseveringlj^ ai^plicd to the exteinial 

 parietes of the chest, may do something. If thick-wind immediate'y 



