A recent experience which has been brought to my attention prompts this note of warning against the advertent or inadvertent use of non-neutralized solutions of salvarsan. A physician administered to two patients, respectively, 0.4 gm. of arsenobenzol in 30 c.c. of water, but failed to neutralize by the addition of sodium hydroxid solution. Both patients developed alarming symptoms. The first patient complained of pain in the epigastrium, in the substernal region and in the left shoulder; later she had abdominal pains with nausea and vomiting. An irritating cough began which at the end of five days had not disappeared. The vein in which the solution had been introduced began to thrombose, and was thickened and painful for a length of 6 inches.
Immediately after the injection, the second patient developed cough and pain in the left shoulder, and the substernal and precordial regions. There was difficulty in breathing, and altogether