As Duguit said a definition for political parties: a group of human beings, the members and the leaders, those who obey and those who command and those who govern and those are governed- the governants and the governés; his definition is true but not enough because by passing the times it takes different definitions as there are definitions for prehistoric parties which still remain personal clans, which are: a crow of individuals bound by a certain solidarity, on the other few leaders or a brand of robbers led by a chief; however the mentioned definitions can suffice for the small communities.
In modern parties: this organization assumes great importance; it constitutes the setting for activity of members, the form imposed on their solidarity: it determines the machinery for the selection of leader, and divides their powers. It often explains the efficiency and strengthen of certain parties the weakness and inefficiency of others. The parties have two kinds of structure; direct and indirect. The direct structure like the present French Socialist party and British Labor party in 1900.The first one has the direct structure however the second one indirect structure.