754 BASTERM COUNTIES VETERINARY MEDICAL ASSOCIATION. 
a disaster; thus, a disease that would under ordinary circumstances de¬ 
velop may slumber for years, indeed, may never appear at all, unless 
some active cause is brought into operation to produce the same. 
The general law is, that all bodily peculiarities tend to become here¬ 
ditary, at the same time changes in structure from causes external are 
supposed to have no effect on the progeny, at least not in the next gene¬ 
ration. How this would act in time it is impossible to speculate. 
One of the most frequent causes of roaring in the horse is here¬ 
ditary ; at the same time, we understand that all the progeny of an 
afflicted stock will not of necessity become roarers. Where a predispo¬ 
sition exists from a cause of this kind, any effect put in operation is 
often sufficient to bring the disease into action; as an instance, great 
physical exertion in young animals, or a thickening of the “mucous 
membrane ” of the air passages as a result of inflammation, constriction, 
or perhaps ulceration of some of the cartilages ; or an effusion of lymph, 
the formation of a false membrane, or even tight reining in of carriage 
horses, may be sufficient; all these may be looked upon as exceptional 
causes, and are often accompanied by “thick wind;” when dyspnoea 
or shortness of breath is added the animal usually suffers from a cough, 
and that too of a peculiar sound, “ a dry, roaring cough.” We find 
in roarers of some years’ standing a considerable difficulty in coughing 
the animal; this arises from the sensibility of the larynx becoming 
diminished and accompanied by “ paralysis of the left recurrent nerve 
and wasting of the muscles of the larynx as a consequence. These horses 
usually “ grunt,” as it is termed. 
As a horse advances in years, roaring not only gets worse, but ani¬ 
mals so afflicted do not thrive so well as others, and are supposed by 
good authorities on the matter to be most peculiarly susceptible to 
disease. 
The horses we find becoming roarers are exactly the reverse of those we 
find affected with broken wind. Broken wind is more peculiar to short, 
punchy animals, with short necks and very coarsely bred, thick-set 
ponies, cobs, and trade horses ; whilst roaring is nearly peculiar to 
hunters, carriage horses of high stature, long necks, and narrow chests, 
sixteen hands high or over. An eye of experience may almost at a 
glance predict animals subject to this malady. This disease, instead of 
having diminished of late years, is alarmingly on the increase. It 
has, so to speak, been growing on us. Many race horses which have 
won considerable stakes, and showed their power of speed on the 
turf by the races they have won for their owners, are roarers. These 
animals finish life in the stud, and the consequence is that roaring 
spreads through long families of race horses, some of the progeny 
being too “ slow ” to train, or from want of staying powers; or 
having some infirmity to prevent their chance of winning a stake. 
Such animals, if mares, degenerate into hacks or cheap hunters ; 
and if stallions, these prodigies, with their various imperfections, are 
used to cover the neighbouring mares for a trifling fee to the groom, 
completely gratifying their owner’s ambition. Being handy they are 
readily made use of by inactive breeders, and by this means the affection 
can never die out. 
The late Professor Spooner was strongly of opinion that two-year old 
racing “ was the exciting cause of this disease.” Personally, I have no 
doubt he had good grounds for the opinion he had formed; matters of 
this kind frequently coming under his observation. 
In seventy per cent, of the post-mortem examinations we make, we find 
the larynx affected. This is real hereditary roaring; at the same time, 
