CHLOROFORM WITH PLBNTY OF Am. The rapidity and depth of this fall is directly dependent upon the concentration of the chloroform, so that if care is taken to give the chloroform with plenty of air it is possible to obtain ansesthesia with very little fall of pressure, for the heart is very little affected by blood containing only a small amount of chloroform. On the other hand, administration of chloroform with plenty of air, continued after complete anDesthesia has been produced, does ultimately overpower the respiration, although the heart is beating sufficiently well to maintain the blood pressure at a fairly good level. Jrhese statements are well illustrated by an experiment on December 11th, 1890 (Fig. 11),21 where chloroform was administered to a rabbit continuously for a long period of time by dropping it on to a cloth placed round the head of the animal in a conical shape, so as to leave a free opening for air about two inches in diameter. Every now and then tie part of the cloth upon which the chloroform was poured was brought closer to the nose and mouth of the animal, and the moment of bringing the chloroform nearer and of removing it again was noted on the kymograph paper. In the tracings a, b, c, d, e, f, Fig. 11, samples of the respiration and bloodpressure curves are given at various times throughout the experiment; as stated already, chloroform was steadily administered during the whole time. In Tracing a, taken before the administration of chloroform at 3.34 we see: mean blood pressure, 64; pulse rate per minute, 222 ; respiration rate per minute, 30. The chloroform was then placed on the cloth, and the effect of bringing the chloroform nearer and removing it further tried for a number of times. An example of the effect produced is given in Tracing b, showing the inhibition of the respiratory movements, the slowing of the pulse, and the rise of blood pressure owing to the stimulation of the trigeminal and pharyngolaryngeal nerves, when the chloroform is more concentrated; immediately the cloth is removed further from the nose the blood pressure returns to its normal condition, and the slowened respiration gradually quickens up to its previous rate. This experiment was repeated again and again with similar results. The effect of the continuous administration of chloroform in this way for 14 minutes ig given in Tracing c, taken at 4.48, where we see: mean blood pressure, 67; pulse rate per minute, 218; respiration rate per minute, 31. Further continuation of the same experiment shows that the inhibition of the respirations and the slowing of the pulse when the chloroform is brought nearer to the nose become less marked; and, finally, after 3.56-that is, 22 minutes after the beginning of the experiment-the blood pressure and the respirations remained absolutely unaffected when the chloroform was brought close to the nose. At the same time, it was noticed that the corneal reflex was entirely abolished. Tracing d, at 3.57, shows the absence of any effect upon temporary concentration of the chloroform, and we see: mean blood pressure, 69 mm.; pulse rate per minute, 204; respiration rate per minute, 42. It is noticeable that at this period, when all reflexes were abolished and the animal was in a condition of complete anaesthesia, the blood pressure was not lower than before the commencement of the experiment, and the only sign of the action of the anaesthetic is to be found in thc quicker respiration. At 3.58 the respiration rate per minute had increased to 46, the pulse tracing and respiration both remaining absolutely regular. At 3.59 the respiration was 45 per minute, at which it remained till 4.1, the mean blood pressure being then 62 mm. Both respiration rate and blood pressure continued steadily to diminish, and at 4.3, when Tracing e was taken, we see: mean blood pressure, 50 mm.; pulse rate per minute, 218; respiration rate per minute, 37. At 4.5 the respiration rate was 35; at 4.7, 31; at 4.8, 29 ; and at 4.9 the respiration had ceased. The termination of the experiment is shown in Tracing f, in which is seen the diminishing force of the diaphragm contractions, with the final rate, and we see: mean blood pressure, 48 mm.; pulse rate per minute, 126; respiration rate per minute, 24. It is noticeable in this case, as in others (Figs. 1, 2, and 3),22