Lymphoid tissue is positioned in the pharynx at the entrance to the digestive tract and respiratory tract in the form of tonsils. In domestic animals three types of tonsils predominate: LINGUAL, PALATINE, and PHARYNGEAL. The speculation is that the lymphoid tissue of the tonsils renders invading organisms less virulent so that the organisms may serve as antigens and thereby stimulate the production of antibodies. TONSILS DO MAKE LYMPHOCYTES.