The anatomic structure of the pharyngeal mucous membrane is characterized by the ample occurrence of lymphocytic elements. They appear singly or in aggregations and in certain nodular formations, which are called lymph follicles. Regular arrangements of such follicles are called tonsils. No matter whether they represent real tonsils or other aggregations of lymphoid tissue, they are homogeneous formations with identical histologic structures, in their entirety called the lymphoid apparatus of the pharynx, and they act alike both in anatomic and in pathologic respects. The acute inflammation of this lymphoid apparatus is called tonsillitis, or angina, the latter name being more comprehensive than the former.
The same kind of lymphoid tissue is present in the conjunctiva of the eye. It appears after the third month of life and is rather thin, in accordance with the minor thickness of the conjunctiva, forming a superficial adenoid layer over the conjunctiva and showing its