Abstract: | There is considerable evidence that Negroes have a tendency toward overgrowth of those connective-tissue components concerned with two functions—protection against infection (macrophages and plasma cells) and repair after injury (fibroblasts and their products). Thus, adaptation to the tropical environment in Africans may have involved a tendency toward connective-tissue overgrowth, as well as hypertrophy of the pigmentary apparatus. Both tendencies may have consequences in terms of: (1) susceptibility to certain chronic diseases; and (2) responses to disease processes or drug therapies. Some of these possible consequences are discussed. |