PULSE RECORDS 73 



ledge, bid fair to revolutionise the technique of cardiovascular 

 diagnosis. 



Records can be obtained of the contraction of both auricles 

 and both ventricles in a large percentage of subjects. In certain 

 conditions the information so derived is of great service, for a 

 particular chamber may fail to contract, its contraction may be 

 imperfect, or it may enter upon its systole too early or too late. 

 Many irregularities of the heart have already received careful 

 analysis along these lines, and knowledge of much clinical import- 

 ance has been gathered in respect of them. In regard to one 

 affection of the heart, the pathological state now known as " heart 

 block," in which the path of conduction from auricle to ventricle 

 is disturbed or broken, and in which a slow pulse and its concomi- 

 tant symptoms constitute the chief features of the disease, a flood 

 of light has been shed upon a condition of which our ignorance 

 was formerly profound. As to the therapeutic action of cardiac 

 drugs, much work has been accomplished, and more remains to 

 be done. A wide field for study has been opened up which awaits 

 careful and painstaking investigations ; and the day, it is hoped, 

 is not far distant when the functions of the heart, and the 

 disturbances of the same, will be profitably referred to at the 

 bedside, in the terms employed by Gaskell in his well-known 

 researches. 



But the study of pulsations in man can never reach that pitch 

 of mechanical perfection to which modern physiological experi- 

 ment has attained, and the conclusions drawn from the more 

 indirect observations on man must ever remain in a measure 

 subservient to, and controlled by, the more direct readings acquired 

 from animals. That emphasis should be laid upon this aspect 

 of the question is imperative, for there is a tendency to-day, 

 frequently noticeable in the consideration of human pulsations, to 

 fly in the face of physiological knowledge, which, as it is unques- 

 tionably of less fallacious origin, should guide, and form the basis 

 of, all conclusions. 



In the following pages the methods recently introduced for 

 the study of the cardiac cycle in the normal subject will be 

 examined ; a critical account will be given of the records obtained 

 in man ; and the information so obtained will be compared and 

 brought so far as possible into line with the correlated knowledge 



