In former articles I have stated that bone is modified by circulatory alterations. The changes are progressive, retrogressive or a combination of both, depending on the predominance of passive or active hyperemia. Alternations of active and passive congestion are more influential in upbuilding than the steady continuation of either. I1 have seen a similar pathologic condition of the ribs in more than 200 cardiovascular cases (fig. 1) of long standing. The changes in bone cells and the modification of matrix and marrow were similar to those in the cases I describe here.
Edema, softening of the matrix and enlarging lacunae relieve the bone cell from imprisonment and pressure and allow it to recover vitality. This process is marked at the borders of cancelli, especially in the spongiosa. The activity of these cells is evident in their proliferation to masses of syncytium resembling callus. I have noted this in the