delivered the opinion of the court. — As a description of the matter of demand or cause of action, so far as to specify the general nature of the action, is all that is usual or necessary in a suit before a justice of the peace, the plaintiff is at liberty, when the cause comes by appeal to the county court, to file a declaration in proper form, upon the particular cause of ac~ *498'£¡on described or specified in the writ. If, however, he falls to file a new declaration within the time prescribed by the rule of court, he is confined to the declaration which comes up from thejustice. In the present case, the writ sued out before the justice contained a full and formal declaration, and that being sufficient both in substance and form, the plaintiff did not avail himself of his right, under the ;rule of the court, to file a new declaration. After, however, the defendant had pleaded non assump-sit to the declaration, and also infancy in bar, the plaintiff moved to amend by adding a count in trover, and the court allowed the amendment. He then moved further to amend, by striking out the original declaration, and this was also allowed. The action proceeded to trial and judgement on the declaration as thus amended $ and the question is, whether the amendments were properly allowed, and if not, whether the allowance of them is an error which can be corrected in this court.
Where a proceeding depends on the discretion of the county court, guided by the particular circumstances of the case, and not on any certain and known rule of law, we have no controul over -it. The granting or refusing of a continuance, of a new-trial, or of an amendment, when within the discretion of the court, though their discretion may be improperly exercised, is not subject to revision in this court on exceptions. But if a new trial, or an amendment, is granted in a case, when the court, by law, have no power to grant it, the party is entitled to relief, -and the error may be corrected on a removal of the cause here. It has been frequently decided in this state, and may be regarded as a settled rule of law, that an amendment cannot be granted, which changes the form of action, or introduces a new count for a new cause of action, not contained in the original declaration. The same rule is laid down in Haynes vs. Morgan, (3 Mass. 208,) and in Phillips vs. Bridge, (11 Mass. 242.) That the original declaration, in this case, was assumpsit, founded on contract, and that trover could not be joined with it, cannot admit of a question. After the plaintiff had been allowed to amend by adding the countin trover, his counsel,being conscious that the two counts could.not be joined, moved and was allowed further to amend, by striking out the original declaration ; and in this way the form of action was effectually changed, by substituting trover for assumpsit. This proceeding, by which the action was altered from an action on contract to an action on tort, was clearly against law ; and though great liberality ought to be exercised in granting amendments for the furtherance of justice, yet to sanction the proceeding in this case,, would be allowing a latitude of amendment, as inconsistent *499with order and regularity in practice, as it is altogether unprecedented. As the amendments were irregularly allowed', and the judgement of the county court must for that cause be reversed, it is unnecessary to consider, whether infancy, after the action was changed from assumpsit into trover, was available as a defence.
Cushman and Marsh, for plaintiff. Everett and Royce, for defendant.Judgement reversed.