There are six cases in which the fatal symptoms came on just after the patient had been rendered insensible, and the inhalation had been discontinued; the operation being about to be commenced. They are numbered 32, 34, 39, 43, 48, and 49. All these cases bear a very close resemblance to each other. In all of them the patient had been made insensible (satisfactorily so as it was thought), when in a few seconds the pulse suddenly stopped, or failed and fluttered just prior to stopping; in Case 32 Dr. Dunsmure thought the time was longer between the discontinuance of inhalation and the cessation of the pulse. The breathing continued a little time after the pulse ceased or failed in all these cases, and there was an absence of the spluttering at the mouth, stretching of the limbs, and other spasmodic actions, which occurred in all the six cases where the heart was paralysed at the beginning of the inhalation, before unconsciousness had been induced, and in some of those when the paralysis of the heart took place at a later period of the inhalation, when the patient had been apparently rendered unconscious, but was not yet insensible. In each of the six cases now under consideration, the fatal event was evidently occasioned by the vapour of chloroform, which remained in the lungs at the moment when the inhalation was discontinued. A portion of this vapour becoming absorbed, and added to that already in the blood, had the effect of paralysing the heart, when it circulated through the coronary arteries.