ded on what the defender alleges, that there is no
such animal as an Egyptian _Pediculus_ or _Louse in rerum
natura_; for though it does not _actually_ exist, it may
_possibly_ exist (if not in _actio_, yet in _potentia_--if
not in actuality, yet in potentiality or capacity); and
whether its existence be in _esse vel posse_, is the same
thing to this question, provided there be _termini habiles_
for ascertaining what it would be if it did exist. But my
doubt is here:--How am I to discover what are the _essentia_
of any Louse, whether Egyptian or not? It is very easy to
describe its accidents as a naturalist would do--to say that
it belongs to the tribe of _Aptera_ (or, that is, a yellow,
little, greedy, filthy, despicable reptile), but we do not
learn from this what the _proprium_ of the animal is in a
logical sense, and still less what its _differentia_ are.
Now, without these it is impossible to judge whether there is
a _convicium_ or not; for, in a case of this kind, which
_sequitur naturam delicti_, we must take them _meliori
sensu_, and presume the _comparatio_ to be _in melioribus
tantum_. And here I beg that parties, and the bar in
general--[interrupted by Lord Hermand: _Your Lordship should
address yourself to the Chair_]--I say, I beg it may be
understood that I do not rest my opinion on the ground that
_veritas convicii excusat_. I am clear that although this
Beetle actually were an Egyptian Louse, it would accord no
relevant defence, provided the calling it so were a
_convicium_; and there my doubt lies.

"With regard to the second point, I am satisfied that the
_Scaraboeus_ or Beetle itself has no _persona standi in
judicio_; and therefore the pursuer cannot insist in the name
of the _Scaraboeus_, or for his behoof. If the action lie at
all, it must be at the instance of the pursuer himself, as
the _verus dominus_ of the _Scaraboeus_, for being
calumniated through the _convicium_ directed primarily
against the animal standing in that relation to him. Now,
abstracting from the qualification of an actual _dominium_,
which is not alleged, I have great doubts whether a mere
_convicium_ is necessarily transmitted from one object to
another, through the relation of a _dominium_ subsisting
between them; and if not necess