142 
ON SOUNDNESS. 
have defined the question of disease, and, with the assistance of a 
“ collateral rule,” settled the disputed points of unsoundness. 
You will admit, I presume, that disease, in itself \ constitutes 
unsoundness : when I say “ disease/' I mean such as every 
body so calls. This being admitted, and disease not being named 
in any of your propositions, it must be, in course, included in your 
“ guiding and determining principle ;” viz. “ that alterations of 
structure, attended with interruption or impairment of function, 
constitute unsoundness.” Now, there are some diseases in 
which function is altered, and not structure; others in which 
structure is altered, and not function: and I have known horses 
to be taken ill, and to die, even without any detectable alteration 
either of structure or function, such as to account for death. I 
therefore feel that I must repeat here what I said in my paper, 
in commenting on the Professor's doctrine, that “ I cannot help 
viewing this definition but as extremely defective.” 
It was the perplexing and intricate question, to say in what 
disease really did consist , which, in my mind, added so much 
confusion to that of “ Soundness,” at the same time that the 
latter embraced other considerations (for I trust I have shown 
that a horse, although free from disease, may yet prove un¬ 
sound ); and it was the fruitless digest of the question which 
induced, or rather compelled me, to introduce “ disease,” unde¬ 
fined as it remained, into my propositions or principles of soutid- 
?iess. Even then, however, it required qualifying; and, accord¬ 
ingly, my third proposition (the second goes for nothing) is 
meant to do this, which I believe it does ; at the same time 
that it, happily, meets other contingencies of soundness. 
For, in regard to your u collateral rule viz. “ that all 
horses with alteration of structure, which does not interfere with 
the function of the part, and which experience tells us is not 
likely to interfere with it for a definite time , are sound,” you will, 
on turning to my positions, find that I had provided for that in 
the same rule as served for all such cases as could not be brought 
under the head of disease; viz. “ by the rule of impairment of func¬ 
tion or capacity .” In regard to lameness in particular, you will 
find I have said (at page 463 of the 2d Vol. of The Veterina¬ 
rian) in my paper, “ in which principles, not only are all lame¬ 
nesses cases of unsoundness, but also every such altered condi¬ 
tion of parts as can be shown, either from their very nature or by 
the aid of experience , to impair present action or diminish its 
natural powers, either of extent or durability.” The clause “ for 
a definite time,” is not mine : it is one to which I cannot sub¬ 
scribe until I hear some definite meaning attached to it. 
