Whichever channel activity works through, it effects some purpose. If rightly directed it achieves the intended purpose; if wrongly directed that intended purpose is not accomplished, but some other result is brought about. The ingenuity of science enables the nose to be used as a passage to convey food to the stomach; but science cannot do this without risk of dangerous consequences; and it is a thing quite beyond the unskilled to effect without inflicting injury. To take a railway ticket to Southampton, wishing to go there, and then to get into a train for Brighton, is called a mistake or going astray; but those who are in the train for Brighton, wishing to go to Brighton, cannot be said to be going astray. The tracks of the railway line are made for the smooth running of the train; if the train slips off the track, it not only has difficulty in proceeding but it also causes damage, ploughing up the land and creating destruction in its path.