Now, my Lords, if there be a _convicium_ at all, it consists in the _comparatio_ or comparison of the _Scaraboeus_ or Beetle with the Egyptian _Pediculus_ or _Louse_.

My first doubt regards this point, but it is not at all founded 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.