. University of Toronto studies. Physiological series. no. 1-98. 1900-28 . and had com-pletely stopped at the end, from which time the volume of the limb re-mained the same until the eighth hour, when the animal died. Theblood pressure remained fairly good until a short time before dose of adrenalin used for testing was cc, 1: 100,000. Through-out the experiment this produced a fall in blood pressure, preceded by aslight rise. The limb responded by a short dilatation (which mayeasily have been due to the preliminary blood pressure rise) followed bya more prolonged constriction un
. University of Toronto studies. Physiological series. no. 1-98. 1900-28 . and had com-pletely stopped at the end, from which time the volume of the limb re-mained the same until the eighth hour, when the animal died. Theblood pressure remained fairly good until a short time before dose of adrenalin used for testing was cc, 1: 100,000. Through-out the experiment this produced a fall in blood pressure, preceded by aslight rise. The limb responded by a short dilatation (which mayeasily have been due to the preliminary blood pressure rise) followed bya more prolonged constriction until the end of the sixth hour when ac-tive dilatation appeared. In other words while the Hmb was in theprocess of dilating as a result of denervation adrenalin caused constric-tion, but when the dilatation from this cause was complete a smallamount of active dilatation occurred from adrenahn. In a second experiment where urethane was given, the cat ( kgm.)lived thirty-three hours. The maximum dilatation was reached be- 506 F. A. HARTMAN, L. G. KILBORN AND LOIS FRASER. Fig. 2. The response of a dener-vated limb to a depressor dose ofadrenalin during atonic andtonic conditions. The hoursrepresent the length of time aftercutting the nerves. The period ofmaximum dilatation was reachedbetween the sixth and seventhhours. Up to tjiat time the vesselsmay be considered atonic; afterthe seventh hour they may be con-sidered tonic; cc, adrenalin1: 100,000 was injected in each upper record at each hourrepresents limb volume, the loweris blood pressure. Cat, (Reduced one-half) tween the sixth and seventh did not remain long at this level,but constriction soon began, continu-ing gradually until the twenty-secondhour, when it ceased. It remained atthis level for the next eight hours. Theamount of this remaining dilatationwas about one-fifth of the dose of adrenalin in each instancewas cc, 1: 100,000. This usuallyproduced a fall in bloo
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