Although a great deal has been written on the subject, much doubt still appears to remain as to the manner in which tuberculosis begins in joints. The consensus of the statements in the more recent textbooks is that the disease starts in the bone ends, spreading thence into the joints, and that primary synovial tuberculosis is a rarity, if indeed it occurs at all. That this uncertainty or difference of opinion should exist in regard to a disease that has been studied so thoroughly is not surprising when it is considered that in the past the opportunities to see specimens at an early stage of the process have been extremely few. It would be difficult by examining the ruins of a burned house to determine in what part the fire started. The purpose in bringing up this subject again is to present the findings in a series of early cases;