[283] What is the difference in principle, it was asked, a few years later, /1/ between the cases where it is admitted that the action will lie, and that of a smith who undertakes to shoe a horse and does not, by reason of which the horse goes lame,--or that of a lawyer, who undertakes to argue your case, and, after thus inducing you to rely upon him, neglects to be present, so that you lose it? It was said that in the earlier instances the duty was dependent on or accessory to the covenant, and that, if the action would lie on the accessory matter, it would lie on the principal. /2/ It was held on demurrer that an action would lie for not procuring certain releases which the defendant had undertaken to get. Five years later another case /3/ came up, which was very like that of the farrier in the reign of Edward III. It was alleged that the defendant undertook to cure the plaintiff's horse, and applied medicine so negligently that the horse died. In this, as in the earlier case, the issue was taken on the assumpsit. And now the difference between an omission and an act was clearly stated, the declaration was held not to mean necessarily anything more than an omission, and it was said that but for the undertaking the defendant would have owed no duty to act. Hence the allegation of the defendant's promise was material, and an issue could properly be taken on it. This decision distinctly separated from the mass of actions on the case a special class arising out of a promise as the source of the defendant's obligation, and it was only a matter of time for that class to become a new and distinct [284] action of contract. Had this change taken place at once, the doctrine of consideration, which was first definitely enunciated about the same time, would no doubt have been applied, and a quid pro quo would have been required for the undertaking. /1/ But the notion of tort was not at once abandoned. The law was laid down at the beginning of the reign of Henry VII., in accordance with the earlier decisions, and it was said that the action would not lie for a failure to keep a promise, but only for negligence after the defendant had entered upon his undertaking. /2/