HYPERTONIC sodium chloride solution has been used intravenously for several different purposes. It has been given to reduce an increased intracranial pressure from edema or haemorrhage ;I to promote intestinal motility in cases of paralytic ileus ;2 and in cholera3 it has been given in order to attract water to the blood, which is viscous owing to extreme dehydration of the body. It has not been in general use for the purpose of raising a lowered blood-pressure, although it has been suggested by Graham4 that a pint of 1.2 per cent sodium chloride should be given to raise the blood-pressure in diabetic coma, as in this condition the tissues lack water and chlorine, and sodium chloride also helps to neutralize acetone bodies. Other workers have put forward objections to the use of hypertonic solutions in the treatment of shock. BaylissY5 in his Oliver Sharpey Lectures of 1918, reviewed the physiological and therapeutic action of various solutions that could be employed by intravenous injection for the treatment of wound shock. He came to the conclusion that a hypertonic solution of sodium chloride was inadvisable as he found the effect transitory and he had noticed unpleasant symptoms of gasping respiration and slowing of the heart. He stated that he believed it undesirable to add to the saline content of the organism, which is an interesting observation when considering the recent treatment of Addison's disease, with its associated low blood-pressure, by sodium If it is undesirable to add to, it seems essential to maintain, the balance of circulating sodium chloride, both on account of its chemical and of its physical properties.MacFee and Baldridge,s also when considering the infusion treatment of shock, state that they ' see small logic in the use of hypertonic solutions ', because of the temporary hydraemia, rapid excretion by the kidneys, and finally a loss rather than gain of fluid.Cushing and Foleyg find that the raised blood-pressure may be an objection to the use of hypertonic saline intravenously for reducing intracranial tension.With due regard for the objections mentioned above, the present series of observations were made on 53 cases. I n 49 of these hypertonic saline was injected intravenously with the object of raising a lowered blood-pressure before, during, or after operation. Most cases received 40 C.C. of a 30 per cent solution (12 grm.) of sodium chloride. Blood-pressure records were kept which show the rapidity and duration of the reaction. The two cases which suggested the possibility of using small quantities of strongly hypertonic salt solution for its rapid stimulating effect on the circulation happened to occur on the same day. In the first case 30 C.C. of 30 per cent sodium chloride solution were injected intravenously, with the aim of reducing intracranial