In Scotland the rule as to erasure is somewhat stricter than in England and the United States, the legal inferences being that such alterations were made after execution.  As to necessary or bona-fide alterations which may be desired by the parties, corrections or clerical errors and the like after a paper is written out but before signature, the rule usually followed is that the deed must show that they have been advisedly adopted by the party; and this will be effected by mentioning them in the body of the writing.  Thus if some words are erased and others superinduced, you mention that the superinduced words were written over an erasure; if words are simply delite that fact is noticed, if words are added it ought to be on the margin and such additions signed by the party with his Christian name on one side and his surname on the other; and such marginal addition must be noticed in the body of the work so as to specify the page on which it occurs, the writer of it and that it is subscribed by the attesting witness.

The Roman rule was that the alterations should be made by the party himself and a formal clause was introduced with their deeds to that effect.

As a general rule alterations with the pen are in all cases to be preferred to erasure; and suspicion will be most effectually removed by not obliterating the words altered so completely as to conceal the nature of the correction.

The law of the United States follows that of England and Scotland in regard to alterations and erasures.

If any one will try the experiment of erasing an ink-mark on ordinary writing paper, and then writing over the erasure, he will notice a striking difference between the letters on the unaltered surface.  The latter are broader, and in most cases, to the unaided eye, darker in color, while the erased spot, if not further treated to some substitute for sizing, may be noticed either when the paper is held between a light and the eye, or when viewed obliquely at a certain angle, or in both cases.

Very frequently it happens that so much of the size and the superficial layer of fibres must be removed that the mark of the ink can be distinctly seen on the reverse side of the paper, and the lines have a distinct border which makes them broader than in the same writing under normal conditions.  If a sharp pen be used there is great likelihood that a hole will be made in the paper, or a sputter thrown over the parts adjacent to the erasure.

The latter effect is produced by the entanglement of the point of the pen among the disturbed fibres of the paper and its sudden release when sufficient force is used to carry it along in the direction of the writing.

It is often of importance to know, in case of a blot, whether the erasure it may partially mark was there before the blot, or whether it was made with the object of removing the latter.

Inasmuch as an attempt to correct such a disfigurement would in all probability not be made until the ink had dried, an inspection of the reverse side of the paper will usually furnish satisfactory evidence on the point.  If the color of the ink be not more distinct on the under side of the paper than the color of other writing where there was no erasure, it is probable that the erasure was subsequent to the blot.