Résumé
Fifteen tonsils were collected during necropsy of cases with sudden death, free from any neoplastic or infectious disease. They were chosen according to three age groups all after the age of 20 years. Group I [20-30 years], Group II [40-50 years] and Group III [60-70 years]. Histological examination revealed gradual diminusion of lymphocytes by aging. This observation was explained on two bases. First, the decline in germinal centers formation [the site for B lymphocytes proliferation]. Second, the decrease in the number of the circulating T lymphocytes. On the contrary, extracellular collagenous fibres were seen to increase markedly by aging to take the place of the diminishing lymphoid tissue. Such observations explained the deteriorating immunologic function of the tonsil after the age of twenty years while the weight as a whole remaining constant