This, although probably rather frequent, has only recently been fully recognized although conditions of the breast designated scrofulous have been long known. There may be isolated caseous masses or they may be more confluent. The caseous matter undergoes softening and opens spontaneously on the surface or is punctured. The result is usually the establishment of a fistulous opening. Probably many of the cases of chronic mastitis and of cold abscess are tubercular.

The tuberculosis of the mamma may be secondary to that of the lungs or other organs, but it may be primary. According to Verneuil the bacilli may find entrance by the milk ducts, and multiply in the glandular structures.

Tuberculosis of the mamma occurs not infrequently in cows which are the subject of tuberculosis of other parts. This fact is of importance because the bacilli frequently find their way into the milk in such cases.