298 BROKEX-WIXD. 



The majority of veterinary surgeons attribute broken-wind to an enipliy 

 sematous state of the lungs. In almost every broken-winded horse which 

 has been examined after death, there has been found dilatation of som.e 

 of the air-cells, and particularly toAvards the edges of the lobes. There 

 has been rupture through the parietes of some of the cells, and they have 

 evidently communicated with one another, and the air could be easily 

 forced from one portion of the cells to another. There was also a cre- 

 pitating noLse while this pressure was made, as if the attenuated membrane 

 of some of the cells had given way. These were the true broken cells, 

 and hence the derivation of the name of the disease. 



Broken-mnd is preceded or accompanied by cough — a cough perfectly 

 characteristic, and by which the horseman would, in the dark, detect the 

 existence of the disease. It is short, suppressed, and hollow, increased 

 when the animal is feeding, or exi^osed to variations of temperature. 

 When the animal is suddenly struck or threatened, there is a low grunt 

 of the same nature as that of roaring, but not so loud. Broken-wdnd is 

 usually preceded by cough ; the cough becomes chronic, leads on to thick- 

 wind, and then there is but a step to broken-wind. It is the consequence 

 of the cough which accompanies catari-h and bronchitis oftener than that 

 attending or following pneumonia, and of inflammation and, probably, 

 thickening of the membrane of the bronchiiB, rather than of congestion of 

 the ail"- cells. 



Laennec, whose illustrations of the diseases of the chest are invaluable 

 to the human surgeon, comes to our assistance, and, while describing em- 

 physema of the lungs of the human being, gives us an explication of 

 broken- wind more satisfactory than is to be foimd in any of our veteri- 

 nary Avriters. He attributes what he calls diy catarrh ' to the partial ob- 

 struction of the smaller bronchial tubes, by the swelling of their inner 

 membrane. The muscles of inspiration are numerous and powerful, while 

 explication is chiefly left to the elasticity of the parts ; then it may happen 

 that the air, which during inspiration had overcome the resistance opposed 

 to its entrance by the tumid state of the membrane, is unable to force its 

 way through the same obstacle during expiration, and remains imprisoned 

 in the cells, as it were, by a valve. The succeeding inspirations introduce 

 a fresh supply of air, and gradually dilate the cells to a greater or less 

 extent ; and if the obstruction is of some continuance, the dilated condi- 

 tion of the cells becomes permanent.' 



Emphysema, or dilatation or rupture of the tissues of the lungs, is of 

 two descriptions : in one, termed vesicular emphysema, the air-cells or 

 vesicles which receive the air in the act of inspiration alone are affected ; 

 they may be dilated, enlarged, each separate cell, but when the vacant 

 space is of considerable size, it is the result of the union of several air- 

 cells broken into one by the stretching or destruction of the partitions 

 that naturally divide and isolate them — in the other, termed the pulmo- 

 nary or interlobular emphysema, the air-cells are ruptured, and the aii* 

 escapes into the cellular tissue which connects them, the cells being dis- 

 tended by a full inspiration ; and the air being unable easily to escape 

 through the obstructed air-tnbes, a strong effort at expiration is made, a 

 rupture takes place, and forms a communication between the air-cells and 

 the cellular tissues. This interlobular cflusion of air may take place in a 

 few minutes or seconds, while the vesicular emphysema, or that limited 

 to the air- vesicles only, is slow and gradual, their permanent dilatation 

 being the work of time ; in both desci'iptions the emi^h^-seniatous portion 

 of the lung is paler, drier, and lighter than the rest, for the air being shut 

 up in these portions, they do not subside, as the adjoining portions do, 

 when left to theii' own elasticity, and in consequ'ence of this they possess 



