With the dissection of Tenon’s capsule and the superior oblique muscle, the work of isolating the other extrinsic muscles will have begun. This work needs no directions except a warning to be careful not to injure the pulley of the superior oblique, and to be careful not to cut away the inferior oblique. The inferior oblique will be found to be near the “pulley.” If the dissection is not carried too close to the origin of the recti muscles, all the muscles may be kept in place.

If the eye has not been previously subjected to the hardening influence of formaldehyde, it may be put into a 5 per cent. solution, and at the end of ten or twelve hours the muscles will have become rigid. They can then be better studied, and may be kept indefinitely. (Fig. 60.)