The thumb is in itself more expressive of character than any other member of the hand. It was D'Arpentigny who wrote "the thumb individualises the man."
Medical science has proved that there is such a thing as a "thumb centre" in the brain and any pressure or disease in that part of the brain shows its effect in the thumb.
A large well-made thumb is the outward and visible sign of a strong-willed, determined person, be he man or woman.
The longer the thumb, the more the power of will rules the actions; the shorter the thumb, the more brute force and obstinacy sways the nature.
The shorter and more thick-set the nail phalange is, giving the appearance of a club, the more ungovernable is the person in his or her temper. Such people have no control over themselves and under the least opposition will fly into a blind rage of fury. This curious formation has been called the "Murderer's Thumb" because so many who have committed murder in a mad fit of passion have been found with this curious formation.
An employee with this class of thumb should never be given any position of authority over others, for he could not curb his ungovernable temper. He would also be absolutely unbalanced in his jealousy, and no woman who has the ambition to live to the usual "threescore-years-and-ten" should risk marriage to a man with one of these thumbs. But as "love is blind" it is useless, I know, to give advice in such a case.
The first joint or nail phalange of the thumb, when long and thin, denotes the opposite of the above characteristics. In such cases the person has the most absolute control over his temper, his will power is also strong but quick and unobtrusive, and in a firm, determined way people with such a thumb manage others and bend those around them to their purpose.
The second joint, if delicately shaped, almost "waist like," indicates tact, diplomacy, and gentleness, also subtlety in argument; but if this part of the thumb be full looking or equal in size to that of the nail phalange, it denotes the person who cares nothing for tact but who, on all occasions, will speak his mind plainly, and with brutal frankness.
When the thumb looks as if it were "tied in" close to the hand, the person is timid, easily frightened by both people and circumstances, narrow-minded in his views, and miserly in his habits. It is a well-established fact that the thumbs of all misers are "tied in" and cramped-looking. It is perhaps this very fear of things and people that in the end makes them misers with their gold.
One need never waste one's time asking a person with one of these cramped-looking thumbs to do a favour, and may God help the business man or woman who ever gets into such a person's clutches!