exception, which prima facie seems just to the defendant,
is unjust to the plaintiff, in which case the latter must protect
himself by another allegation called a replication, because it parries
and counteracts the force of the exception. For example, a creditor may
have agreed with his debtor not to sue him for money due, and then have
subsequently agreed with him that he shall be at liberty to do so; here
if the creditor sues, and the debtor pleads that he ought not to be
condemned on proof being given of the agreement not to sue, he bars the
creditor's claim, for the plea is true, and remains so in spite of the
subsequent agreement; but as it would be unjust that the creditor should
be prevented from recovering, he will be allowed to plead a replication,
based upon that agreement.

1 Sometimes again a replication, though prima facie just, is unjust
to the defendant; in which case he must protect himself by another
allegation called a rejoinder:

2 and if this again, though on the face of it just, is for some reason
unjust to the plaintiff, a still further allegation is necessary for his
protection, which is called a surrejoinder.

3 And sometimes even further additions are required by the multiplicity
of circumstances under which dispositions are made, or by which they
are subsequently affected; as to which fuller information may easily be
gathered from the larger work of the Digest.

4 Exceptions which are open to a defendant are usually open to his
surety as well, as indeed is only fair: for when a surety is sued the
principal debtor may be regarded as the real defendant, because he can
be compelled by the action on agency to repay the surety whatsoever he
has disbursed on his account. Accordingly, if the creditor agrees with
his debtor not to sue, the latter's sureties may plead this agreement,
if sued themselves, exactly as if the agreement had been made with
them instead of with the principal debtor. There are, however, some
exceptions which, though pleadable by a principal debtor, are not
pleadable by his surety; for instance, if a man surrenders his property
to his creditors as an insolvent, and one of them sues him for his debt
in full, he can effectually protect himself by pleading the surrender;
but this cannot be done by his surety, because the creditor's main
object, in accepting a surety for his debtor, is to be able to have
recourse to the surety for the satisfaction of his claim if the debtor
himse