The next case is of the same reign, and goes further. /1/ The writ set forth that the defendant undertook to cure the plaintiff's horse of sickness (manucepit equum praedicti W. de infirmirate), and did his work so negligently that the horse died. This differs from the case of laming the horse with a nail in two respects. It does not charge any forcible act, nor indeed any act at all, but a mere omission. On the other hand, it states an undertaking, which the other did not. The defendant at once objected that this was an action for a breach of an undertaking, and that the plaintiff should have brought covenant. The plaintiff replied, that he could not do that without a deed, and that the action was for negligently causing the death of the horse; that is, for a tort, not for a breach of contract. Then, said the defendant, you might have had trespass. But the plaintiff answered that by saying that the horse was not killed by force, but died per def. de sa cure; and upon this argument the writ was adjudged good, Thorpe, J. saying that he had seen a man indicted for killing a patient by want of care (default in curing), whom he had undertaken to cure. [277] Both these cases, it will be seen, were dealt with by the court as pure actions of tort, notwithstanding the allegation of an undertaking on the part of the defendant. But it will also be seen that they are successively more remote from an ordinary case of trespass. In the case last stated, especially, the destroying force did not proceed from the defendant in any sense. And thus we are confronted with the question, What possible analogy could have been found between a wrongful act producing harm, and a failure to act at all? I attempt to answer it, let me illustrate a little further by examples of somewhat later date. Suppose a man undertook to work upon another's house, and by his unskilfulness spoiled his employer's timbers; it would be like a trespass, although not one, and the employer would sue in trespass on the case. This was stated as clear law by one of the judges in the reign of Henry IV. /1/ But suppose that, instead of directly spoiling the materials, the carpenter had simply left a hole in the roof through which the rain had come in and done the damage. The analogy to the previous case is marked, but we are a step farther away from trespass, because the force does not come from the defendant. Yet in this instance also the judges thought that trespass on the case would lie. /2/ In the time of Henry IV. the action could not have been maintained for a simple refusal to build according to agreement; but it was suggested by the court, that, if the writ had mentioned "that the thing had been commenced and then by not done, it would have been otherwise." /3/