A full pulse is not always strong, nor is a small pulse necessarily weak. Mention has been made already of the tense, corded pulse met with in acute peritonitis, and sometimes in enteritis. Gastric inflammation, with nausea, may exhibit a depressed pulse, weak and but little accelerated. Under still other circumstances we may find a full pulse which is soft, easily compressible, even gaseous. Most frequently a feeble pulse is rapid, and a very rapid pulse is weak. Slowness, in marked degree, attends apoplexy, opium narcotism, and fracture of the skull compressing the brain. Functional disturbance of the heart may occasionally exceed in effect these causes of retardation. I have met, under such circumstances, with a pulse of 20 in the minute; one of 18 has been recorded. A few apparently healthy persons have habitually a pulse with but 40 or 50 beats in the minute. Quickness in each beat may occur, while a long interval makes the rate per minute slow. The jerking pulse of aortic regurgitation is the most remarkable example of this. Galabin asserts that without imperfection of the valves of the aorta a decidedly abrupt pulse may attend great lowering of arterial tension. Something of the same kind may be noticed in the temporarily excited pulse of very nervous subjects under agitation. Dicrotism, or reduplication of the pulse-beat, is not uncommon in typhus and typhoid fever. Here relaxation of the heart as well as of the blood-vessels appears to allow a momentary interruption in the succession of the arterial upon the cardiac systole.[39] [Footnote 39: An exceptional phenomenon, noticed by a few observers, is the recurrent pulse; _i.e._ a pulsation felt below the finger, whose pressure interrupts the flow of blood through an artery. It may be explained by supposing unusual fulness of the vessels (local, if not general) with, at the same time, relaxation of their walls; bearing in mind, also, the manner of anastomosis of the radial and ulnar branches which favors recurrence.] Intermittence and irregularity of the pulse are not exactly the same thing. Occasional intermittence may be merely a nervous symptom or a muscular twitch of the heart, like the twitches now and then occurring without significance in voluntary muscles. Persistent intermittence, with feebleness of the pulsations (these being generally somewhat rapid), is among the signs of dilatation of the heart. It is possible for intermittence of the radial pulse to accompany regularity in the heart-beat. This usually results from narrowing (stenosis) of the aortic valvular outlet from the left ventricle. Only a certain number of impulses fairly reach the more distant arteries. This symptom may result also from fatty degeneration of the heart. Absence of pulse in one radial vessel, while it is present in the other, shows the presence of an obstacle to the circulation on one side, which may be an aneurism, or an embolus plugging the artery.