The ornamental design for physiological scale, as shown and described.
FIG. 1 is a perspective view of the physiological scale, with the top and two sides shown, according to an embodiment of the present design;
FIG. 2 is a perspective view of the physiological scale, with the bottom and two sides shown, according to an embodiment of the present design;
FIG. 3 is a top view of the physiological scale, according to an embodiment of the present design;
FIG. 4 is a bottom view of the physiological scale, according to an embodiment of the present design;
FIG. 5 is a side view of the physiological scale, which is identical to the other side which is parallel thereto, and according an embodiment of the present design; and,
FIG. 6 is a side view of the longer side of the physiological scale, which is identical to the other side which is parallel thereto, and according an embodiment of the present design.