CLINICAL OBSERVATIONS ON ROARING. 
813 
would, perhaps, be approximately correct : Mares, 600; geld¬ 
ings, 395; stallions, 5. 
If we assume for purposes of study that our 25 cases would 
exist among 10,000 horses then the following table would show 
the inequality of vulnerability to roaring as influenced by sex : 
These very brief data may be quite misleading, but they are 
in our judgment in accord with our prior "observations where 
no statistics were preserved, unless that the ratio of stallions af¬ 
fected is too low. 
If roaring is hereditary, environment should* play little, if 
any part, in determining the absence or presence of a disease, 
but in our observations we have never seen roaring in an un¬ 
housed horse. This is interesting in conjunction with the data 
above given as to sex. Stallions are as a rule constantly 
stabled. Geldings are used for work purposes only, and are 
largely sold into cities and quite constantly stabled, while a 
large proportion of mares are kept on farms and are more largely 
allowed the freedom of the pasture. 
These, to us, are the chief arguments against the heredity 
of roaring, while probably the chief, if not the only weighty evi¬ 
dence for heredity, is the frequent occurrence of roaring among 
the progeny of affected parents, but if climate and housing ex¬ 
ert a distinct influence upon its cause or prevention, then it 
must largely destroy the value of this fact as a proof of hered¬ 
ity. If given climate, food, housing or other environment 
causes or prevents roaring, then if these conditions be present 
roaring naturally ensues if parents be roarers, and equally so 
if they are not roarers, and the strongest suggestion of the prob¬ 
able advent of roaring in a young horse would be that his sire 
or dam contracted the disease under the same conditions in 
which 'he is placed. 
The question needs careful study. In horse shows stallions 
which roar are excluded from competition, but their progeny, 
shown without their sire, are eligible ! If the disease is hered¬ 
itary the action is hypocritical, if not hereditary much injury is 
done by damaging the repute of excellent sires. 
