p>The most important of these laws is the Law of Habit. In obedience to this law, the next idea to enter the mind will be the one that has been most frequently associated with the interesting part of the subject you are now thinking of.
The sight of a pile of manuscript on your desk ready for the printer, the thought of a printer, the word "printer," spoken or printed, calls to mind the particular printer with whom you have been dealing for some years.
The word "cocoa," the thought of a cup of cocoa, the mental picture of a cup of cocoa, may conjure with it not merely a steaming cup before the mind's eye and the flavor of the contents, but also a daintily clad figure in apron and cap bearing the brand of some well-known cocoa manufacturer.
If a typist or pianist has learned one system of fingering, it is almost impossible to change, because each letter, each note on the keyboard is associated with the idea of movement in a particular finger. Constant use has so welded th