Innumerable examples of this condition have been described and various theories elaborated. Apart from such cases, it is a matter of common observation that if any one be asked to write synchronously with the two hands, his left hand will tend spontaneously to adopt the mirror form.[232] The experiment may be tried on some one who has never made the attempt to write with the left hand, and has never heard of mirror writing. Ask him to abandon his left hand completely to the movements it may be constrained to fashion while the right hand is tracing the required words, and let his eyes be closed; in practically every case the left will make mirror characters. It may therefore be contended that mirror writing is the natural writing of the left hand, an opinion supported by Vogt, Durand, etc., and more recently by Ballet,[233] who remarks that this variety of writing for the left hand is natural in left-handed people who have not been influenced by education. The actual form of the characters is of little significance. We have often repeated the experiment and substituted Greek, German, typographic and stenographic letters, but always with the same result. It is perhaps worthy of note that in simultaneous writing considerable modification of the letters traced by the right hand occurs; they become hesitating and childish; the lines are sinuous and irregular, and the characters themselves ill distinguished. The same holds good for drawings. On the other hand, the first attempt of the left to make mirror writing to order is frequently laborious. Mingled with true mirror characters will be found ordinary letters automatically traced, for automatism of left-hand movements is not the inevitable sequel of automatism of right-hand movements. From time to time the visual image of a normal letter rises in the mind, an image which does not correspond to that which the hand is endeavouring to express, whence doubt, reflection, arrest, and, usually, error. If, however, the subject allows his left hand to write, without preoccupying himself with the shape of the letters it is making, or with his eyes shut, automatism reasserts its sway and mirror writing results. Of course a person who is asked for the first time to use his left hand in writing may force himself to trace ordinary characters, but to do so he must evoke the visual image of each letter and seek to reproduce the contours of this image slowly, yet often inaccurately. There is nothing automatic in this. Hence it is that ordinary writing with the left hand demands prolonged education and patient effort, and may never attain any rapidity, whereas mirror writing with the same hand is acquired with facility in a more or less automatic manner. It may well be that the natural left-hand mirror writing of which we are speaking is a purely motor phenomenon, since the calling up of the visual images of letters, so far from proving of assistance, is calculated rather to obscure and hamper it.