3. General rule as to competency of principals.

It may be stated as a general proposition that whatever a person has power to do himself he may do by means of an agent1. The converse proposition similarly holds good; what a person cannot do himself he cannot do by means of an agent2. It is, in general, necessary to ascertain who is legally competent to act or contract3 in order to know who is competent to be a principal.

There are, however, two exceptions to the general rule that a person may do by means of an agent whatever he has power to do himself, and these are: