10 



CHAPTER XXII. 



Definition. — A 'peculiar diseased condition, marled hy 2x1 r- 

 oxysmal attacks of dlfficidty in breathing, often tulth much 

 distress, and a v.'Jieeziug noise in the respircdion ; these 

 symptoms ajjpearing to depend upon spasm of the encircling 

 bronchial muscles. The cdtacks are of uncertain occurrence 

 and duration; they may p^'^^s completely off , or they may be 

 prolonged into the aggregation of symptoms spoken of as 

 broken-wind. 



Nature and Causation. — That a condition apparently de- 

 pendent for its production on the existence of tonic or clonic 

 spasm of the bronchial muscular tissue may be encountered as 

 a distinct and separate affection in the horse I feel satisfied. 

 That it has not oftener been specially alluded to I believe may 

 be accounted for from the facts — hrst, that it bears a close 

 resemblance in many of its features to what we speak of as 

 ' broken-wind ;' second, because it not unfrequently appears as 

 a precursor of this latter condition. From these associations 

 it seems to me that it has usually been mixed up and con- 

 founded with that and the terms regarded as synonymous. In 

 makmg this separation I believe we are warranted both by the 

 symptoms and history of many cases, and by the manner in 

 which they severally respond to or are acted upon by thera- 

 peutic agents. That these conditions are dependent on different, 

 or rather dissimilar, pathological states may not be so easy of 

 demonstration anatomically ; still the differences in their 

 symptoms and development, together with the variations in 

 action upon them of similar therapeutic agents, seem to indicate 

 a non-similarity of textural lesions. 



In pure asthma the attacks are uncertain as to occurrence 

 and periods of duration, and they are in the same animal 

 usually separated from each other by considerable, often by 

 long intervals of time ; they are truly intermittent. The same 

 cannot be said of ' broken- wind,' which, when once established, 

 although marked by remission and accession of symptoms, is 

 never intermittent. 



The mingling in description and classification of these two 



