In many of the experiments on shock which I have previously reported, sodium barbital was used as the anesthetic. Parsons and Phemister used ether or sodium barbital or either of these supplemented by morphine in most of their experiments. Similar findings were reported1 by the two groups of investigators. Sodium barbital in the dosages employed in these experiments produces unconsciousness, an acceleration of the pulse rate, a decline in the pulse pressure, occasionally a drop in the arterial blood pressure, infrequently early death and frequently a moderate amount of capillary congestion and hemorrhage in some of the organs of the body. Most of these changes are produced by any agent which will produce profound anesthesia for a number of hours. It is unfortunate that the experimental production of a great many pathologic conditions has for humane reasons to be accompanied by a complicating factor such as an anesthetic. However,