In some cases bills and notes are declared void by statute. An illustration of such a prohibition on the degree of understanding possessed by the party sought to be charged. A man of weak mind, if not a lunatic or a fool, can contract. An epileptic or enfeebled mind has been held competent to convey property. A person born deaf and dumb is not necessarily an idiot. And no mere want of business capacity, nor even monomania, will in the absence of fraud prevent a party from being bound upon a ill, note or indorsement. The mental incompetency to avoid such a contract must amount to inability to understand the nature of the contract, and to appreciate its probable consequences; and this only, upon being established, will be allowed as a defense. But, once established, the question of the binding liability of this contract depends upon the fact whether the party dealing with him knew or did not know that he was dealing with a lunatic. In the absence of anything being shown upon the subject, the courts lean to the presumption that the party had this knowledge. And if he possess such knowledge then the bill, note or indorsement as between the parties is void, and will not be enforced.' Norton on Bills and Notes, Sec. 98.

4 Howard vs. Simpkins, 70 Ga., 322.

5 Norton on Bills and Notes, Sec. 96.

The most common illustrations of this class of statutory provisions at the present time are those relating to usurious negotiable instruments.8

A note declared void by statute cannot be recovered on, even by a bona fide holder for value.7 This rule does not apply, however, when the statute merely declares the consideration to be illegal.8