bone-nippers in one piece, either toward the head or sacrum as is the more convenient. The laminæ may be cut by a chisel instead of a saw. The straight-edged or curved single chisel, the “tomahawk” chisel, or the double-bladed chisel of _Esquirol_ may be employed. The latter instrument has adjustable chisel-blades that can be set to include the spinous processes. These blades are very strong and short, and have convex cutting edges. The use of a wooden mallet (Fig. 17) is to be preferred to that of the steel hammer in driving chisels of any type. The straight, curved and tomahawk chisels are held with their cutting edges directed slightly outwards. The _Amussat rhachiotome_ is a chisel-knife with a curved metallic handle, the cutting edge running along the length of the chisel. When set at an angle of 45° to the laminæ it is driven through them by means of blows from a wooden mallet delivered upon the chisel-back over the cutting edge. The _Brunetti chisels_ are shown in Fig. 15. In using these to open the spinal cord posteriorly, a block should be placed beneath the abdomen so as to raise the lumbar vertebræ above the level of the dorsal. The intervertebral ligaments of the last lumbar vertebræ are then cut through with the belly of the cartilage-knife held at right angles to the spine. The laminæ and spinous process of the last lumbar vertebra are then cut out with the straight-edged chisel or bone-forceps, exposing the canal. The _right_ and _left_ Brunetti chisels are then alternately used, beginning usually with the “left” chisel, the blunt probe-point being introduced into the canal, while firm pressure downward is made upon the handle, while at the same time the cutting edge is driven through the outer borders of the vertebral arches by blows from a wooden mallet delivered upon the head of the handle. Great care must be taken to keep the cut at the same level throughout. It is better, however, to cut too high rather than too low. In the latter case the cord may be injured, while in the former the bone may later be easily trimmed off sufficiently without causing any damage. The arches of three to four or even more vertebrae may be cut without removing the chisel. The same thing is then done on the other side, using the “right” chisel. The loosened portion of bone and ligaments is then cut or torn off with the bone-forceps or nippers. The cut bone should not be touched with the hands because of the danger of injury and subsequent infection from the sharp spicules and splinters of bone. As the canal is opened the block under the body is pushed towards the head, the object being always to cut _down hill_ and not upward. When the cervical region is reached the head of the cadaver should be firmly held by an assistant so as to give sufficient resistance to the blows of the mallet. The skilful use of the Brunetti chisels is difficult to acquire and a great deal of practice is necessary, but when once the knack is