212 THICK -WIND. 



and expirations being rapid, forcible, but equal. In the second, the breathing is also 

 hurried, but the inspiration does not differ materially from the natural one, while the 

 expiration is difficult, or doubly laborious, 'i'he changes of structure which accom- 

 pany tliese states of morbid respiration are as opposite as can be imagined. Indura- 

 tion of the substance of the lungs, diminution of the number or the calibre of the air- 

 passages, are the causes of ihick-wind. 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 by each. In brukeii-v ,i i! there is rupture 

 of the air-cells, and an unnatural inter-comnmnicatiou between i. . m in the same 

 lobule, or between those of the neighbouring lobuli. The structure cf the lung, and 

 the discharge of function, and the treatment, too, being so different, 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 with 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 rottainess 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 keputizeil, — its structure bears considerable 

 resemblance to that of the liver. This may occur in patches, ci it may involve a 

 considerable portion of the lung. 



If a portion of the lung is thus rendered impervioVis, the remainder will have addi- 

 tional work to perform. The same quantity of blood must be su])plied with air ; and 

 if the working part of the machine is diminished, it must move with 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 enough by his sad distress when he is urged to unusual or continued 

 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 heaving of the 

 flanks; but by auscultation alone can we ascertain its progress. The increase of the 

 crepitus will tell us that the mischief is beginning, and the cessation of the murmur 

 will clearly mark out the extent of the congestion. 



The inflammatory stage of the disease having passed, and comparative health being 

 restored, and some return to usefulness having been established — the horse being now 

 thick-winded — auscultation will be far more valuable than is generally imagined. It 

 will faithfully indicate the quantity of hepatization, and so give a clue to the degree 

 of usefulness, or the extent to which we may tax the respiratory system ; and it will 

 also serve to distinguish, and that very clearly, between this cause of ihick-wind, 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 what means we can excite 

 the absorbents to take up the solid organised mass of liepatization, or restore tne 

 membrane of the cells, and the minute vessels ramifying 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 perseveringly 

 applied to the external parietes of the chest, may do something. If thick-wind imme- 

 diately followed bronchitis, it would certainly be justifiable practice to blister the 

 brisket and sides, and tliat repeatedly ; and to administer purgatives, if we dared, or 

 diuretics, more effectual than the purgatives, and always safe. 



Our attention must be principally confined to diet and management. A thick 

 winded horse should have his full proportion, or rather more than his proportion ot 

 corn, and a diminished quantity of less nutritious food, in order that the stomach may 

 never be overloaded, and press upon the diaphragm, and so upon the lungs, and 

 increase the labour of these already over-worked organs. Particular care should be 

 t«ken that the horse is not worked immediately after a f^I' neal. The overconiinjr 



