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Scientific Proceedings (51). 



unimpaired for several hours. When this anesthetic dose is 

 exceeded, the first striking effect is upon the spontaneous respira- 

 tion which may be rapidly abolished. For instance, if complete 

 anesthesia has been accomplished by a dose which we term 

 ether" or ether" and now "full ether" is turned on, the 

 respiration may stop completely within one to five minutes. At 

 this stage blood pressure is not impaired. When, however, "full 

 ether" is continued the blood pressure begins to come down. 

 The descent is very gradual and slow. It is rarely less than one 

 hour, in some cases it may be even several hours, before the 

 pressure reaches the dangerous stage. At that stage the blood 

 pressure may not be above 20 or 25 millimeters of mercury, and 

 the pulse pressure also considerably reduced. However, even at 

 this stage when the ether is turned off, the pressure may begin to 

 rise at once ; although some time has to pass before the respiration 

 returns, and there is still another interval before reflexes and 

 consciousness return. The duration of the returning ascent is 

 shorter than the duration of the descent. It is, however, not 

 absolutely necessary to shut off the ether completely; a reduction 

 to "half ether" is, as a rule, soon followed by a return to a degree 

 of blood pressure which is sufficient to obviate danger. 



The ready abolition of the respiration by ether is a practically 

 important phenomenon; it may serve as an indication that the 

 etherization has entered the toxic zone. It is a danger signal, 

 and since hours may pass before the real danger will be arrived at, 

 it is a safe and very valuable signal. 



It is different with chloroform. In doses which are un- 

 doubtedly in excess of the anesthetic dose, respiration and blood 

 pressure go down practically together, and this in a comparatively 

 short time. When the administered dose is only slightly in excess 

 of the reliably anesthetic dose, the impairment of respiration does 

 not set in as early as under ether intoxication ; but when this sets 

 in, blood pressure begins to fall also, although the respiration may 

 in some cases cease fifteen or twenty minutes before the fall of 

 blood pressure reaches the danger point. Respiration, perhaps, 

 resists chloroform intoxication slightly longer than that of ether, 

 while blood pressure is affected much more rapidly and profoundly 

 by chloroform than by ether. The zone separating the safe 



