96 A MANUAL OF PHYSIOLOGY 



addition, a real sexual difference. The position of the body 

 exercises a small, but relatively constant, influence on the 

 rate, which is greater in the standing than in the sitting 

 posture, and greater in the latter than in the recumbent 

 position. And this is true even when muscular action is as 

 far as possible eliminated by fastening the person to a board. 

 The pulse is further affected by the respiratory movements, 

 especially when they are exaggerated in forced breathing, 

 being accelerated during each inspiration (p. 249). It is 

 also increased by the taking of food, and especially of 

 alcoholic stimulants, by muscular exercise, in fever and 

 many other pathological conditions, and by a high external 

 temperature. A warm bath, for example, causes a very 

 distinct acceleration of the heart ; and Delaroche found that 

 in air at the temperature of 65 C. his pulse went up to 160. 

 A cold bath may depress the pulse-rate to 60, or even less. 

 During sleep it may fall to 50. It is greatly influenced by 

 psychical events, and that in the direction either of an 

 increase or a decrease. Finally, it ought to be remembered 

 as of some practical importance that the pulse- rate in women 

 and children, but particularly in the latter, is less steady 

 than in men, and more apt to be affected by trivial causes. 

 And it is a good general rule to let a short interval elapse 

 after the finger is laid on the artery before beginning to 

 count the pulse, so that the acceleration due to the agitation 

 of the patient may have time to subside. 



Various Characters of the Pulse. Certain terms which have 

 come down from the older medicine, and are still used clinically to 

 describe various conditions of the circulation as investigated by 

 feeling the pulse, must here be briefly touched on : 



' Hard ' pulse (pulsus durus]. Here the mean blood-pressure is 

 high, the vessels are considerably distended, and the pulse therefore 

 feels hard. With a ' soft ' pulse (pulsus mollis) the mean blood- 

 pressure is low. 



With a ' quick ' pulse (pulsus celer] the artery is rapidly distended 

 by the pulse-wave. With a ' slow ' pulse (pulsus tardus) the disten- 

 sion is slow. 



The terms ' strong ' pulse (pulsus fortis} and ' weak * pulse (pulsus 

 debilis) refer to the amount by which the pulse-wave increases the 

 blood-pressure at the point. 



1 Large ' pulse (pulsus magnus) and ' small ' or ' thready ' pulse 



