Once the operation is begun, and remembering that the depressing influences which tend to reduce blood pressure are transmitted through the afferent nerves, we may take advantage of Crile’s suggestions and temporarily paralyze them, by exposing them and injecting directly into the nerve trunks two or three drops of 1 per cent. cocaine solution. This should be done before division of the main trunks and at a point above the line of section. It is possible during an amputation, by taking a little extra time and pains, to “block off,” as it is called, the nerves in this way and prevent their conveying any depressing sensation. At other times, as in operations on the mouth, and especially the larynx, cocaine solution may be used locally, as by the spray, and the same effect produced. Cocaine seems to be a protoplasmatic poison which inhibits nerve action. In the description of the treatment of shock there has been little reference made to the result of loss of blood as such. In cases where this has already occurred, or cannot be prevented, it should be atoned for by the infusion of saline solution, either by intravenous introduction or by hypodermoclysis, _i. e._, its injection into the loose connective tissues in various parts of the body. While a special apparatus has been devised for this purpose, a sterile fountain syringe with an ordinary aspirator needle will be found to be sufficient for nearly all purposes. The erethistic, or extremely restless type of shock, may be profitably treated by small doses of morphine given subcutaneously. The _question of immediate operation or delay_ should be carefully considered. Shock is often alleviated by prompt removal of mutilated limbs or parts whose fragments, while still connected with the trunk, seem rather to perpetuate the condition, especially if the principal nerve trunks are cocainized. In serious cases intravenous infusion should be practised. After commencing with the anesthetic, while scrubbing and cleansing the field of operation it is advisable to scrub an arm where it may be necessary to expose a vein, or the skin at several points, where a needle may be entered, so that there may be no delay for this purpose should infusion or hypodermoclysis be suddenly required. CHAPTER XIX. ABSTRACTION OF BLOOD; COUNTERIRRITATION; PARACENTESIS; TRANSFUSION; CATHETERIZATION; SKIN GRAFTING; BANDAGING.