There is, however, an important consideration, which has not yet been adverted to. It is undoubtedly possible that those who have the making of the law should deem it wise to put the mark higher in some cases than the point established by common practice at which blameworthiness begins. For instance, in Morris v. Platt, /2/ the court, while declaring in the strongest terms that, in general, [116] negligence is the foundation of liability for accidental trespasses, nevertheless hints that, if a decision of the point were necessary, it might hold a defendant to a stricter rule where the damage was caused by a pistol, in view of the danger to the public of the growing habit of carrying deadly weapons. Again, it might well seem that to enter a man's house for the purpose of carrying a present, or inquiring after his health when he was ill, was a harmless and rather praiseworthy act, although crossing the owner's boundary was intentional. It is not supposed that an action would lie at the present day for such a cause, unless the defendant had been forbidden the house. Yet in the time of Henry VIII. it was said to be actionable if without license, "for then under that color my enemy might be in my house and kill me." /1/ There is a clear case where public policy establishes a standard of overt acts without regard to fault in any sense. In like manner, policy established exceptions to the general prohibition against entering another's premises, as in the instance put by Chief Justice Choke in the Year Book, of a tree being blown over upon them, or when the highway became impassable, or for the purpose of keeping the peace. /2/ Another example may perhaps be found in the shape which has been given in modern times to the liability for animals, and in the derivative principle of Rylands v. Fletcher, /3/ that when a person brings on his lands, and collects and keeps there, anything likely to do mischief if it escapes, he must keep it in at his peril; and, if he does not do so, is prima facie answerable for all the [117] damage which is the natural consequence of its escape. Cases of this sort do not stand on the notion that it is wrong to keep cattle, or to have a reservoir of water, as might have been thought with more plausibility when fierce and useless animals only were in question. /1/ It may even be very much for the public good that the dangerous accumulation should be made (a consideration which might influence the decision in some instances, and differently in different jurisdictions); but as there is a limit to the nicety of inquiry which is possible in a trial, it may be considered that the safest way to secure care is to throw the risk upon the person who decides what precautions shall be taken. The liability for trespasses of cattle seems to lie on the boundary line between rules based on policy irrespective of fault, and requirements intended to formulate the conduct of a prudent man.