A defendant who does not bring in as a third party defendant a person who is liable to him for all or part of the principal demand does not on that account lose his right or cause of action against such person, unless the latter proves that he had means of defeating the action which were not used, because the defendant either failed to bring him in as a third party defendant, or neglected to apprise him that the suit had been brought. The same rule obtains with respect to a defendant in reconvention who fails to bring in as a third party defendant a person who is liable to him for all or part of the reconventional demand.