CONDITIONS AFFECTING THE PULSE-RATE. 



I07 



of the pulse is usually increased when the respirations are deeper, but not more numerous, i.e., 

 rapid shallow respirations do not affect the frequency of the pulse, but deep respirations do. 

 [The frequency may be regular or irregular with regard to time.] 



(2) Celerity or Rapidity. If the pulse-wave is developed, so that the distension of the artery 

 slowly reaches its height, and the relaxation also takes place gradually, we have the p. tardus 

 or slow or long pulse ; the opposite condition gives rise to the p. celer or quick or short pulse. 

 The rapidity of the pulse is increased by quick action of the heart, power of expansion of the 

 arterial walls, easy efflux of blood owing to the dilatation of the small arteries, and by nearness 

 to the heart. [The quickness has reference to a single pulse-beat, the frequency to a number of 

 beats. ] In a quick pulse, the curve is high and the angle at the apex is acute, while in a slow 

 pulse the ascent is low and the angle at the apex is large. 



(3) Conditions affecting the Pulse-Kate. Frequency in Health. In man the normal pulse - 

 rate = 71 to 72 beats per minute, in the female about 80. In some individuals the pulse-rate 

 may be higher (90 to 100), in others lower (50), and such a fact must be borne in mind. 



(a) Age : 



(c) The pulse-rate is increased by muscular activity, by every increase of the arterial blood- 

 pressure, by taking of food, increased temperature, painful sensations, by psychical disturbances, 

 and [in extreme debility]. Increased heat, fever, or pyrexia increases the frequency, and as a 

 rule the increase varies with the height of the temperature. [Dr Aitken states that an increase 

 of the temperature of 1 F. above 98 F. corresponds with an increase of ten pulse-beats per 

 minute ; thus 



This is merely an approximate estimate. ] It is more frequent when a person is standing than 

 when he lies down. Music accelerates the pulse and increases the blood-pressure in dogs and 

 men. Increased barometric pressure diminishes the frequency. 



The Variation of the Pulse-Rate during the Day. 3 to 6 a.m. =61 beats ; 8 to 11 J a.m. =74. 

 It then falls towards 2 p.m. ; towards 3 (at dinner-time) another increase takes place and goes 

 on until 6 to 8 p.m. =70; and it falls until midnight = 54. It then rises again towards 

 2 a.m., when it soon falls again, and afterwards rises as before towards 3 to 6 a.m. 

 [Pulse-Rate in Animals. (Colin).'] 

 Per Min. 



Lioness, 



Tiger, 



Sheep, 



Goat, 



Leopard, 



Wolf (female), 



Hyaena, 



Dog, 



Cat, 

 (4) Variations in the Pulse-Rhythm (Allorhythmia). On applying the fingers to the normal 

 pulse, we feel beat after beat occurring at apparently equal intervals. Sometimes in a normal 

 series a beat is omitted = piilsus intermittens, or intermittent pulse. [In feeling an inter- 

 mittent pulse, we imagine or have the impression that a beat is omitted. This may be due to a 

 reflex arrest of the ventricular contraction, caused by digestive derangement, in which case it 

 has no great significance ; but if it be due to failure of the ventricular action, intermittent pulse 



