1913.] 



Electrical Axis of the Human Heart. 



517 



(which in themselves act as a condenser of considerable polarisation capacity, 

 e.g. in one measured case about 10 mf.), supplemented by an added condenser 

 in circuit, we are rendered independent of alterations of resistance ; the 

 galvanometer is practically converted into an electrometer. 



5. Influence of Position and of Respiration. 



The influence of slight alterations of position of the body upon the electrical 

 record both as regards form and as regards amplitude is trifling. I did not 

 notice any such influence in my first observations. Einthoven has subse- 

 quently found that in the recumbent posture turning from the left over to 

 the right side alters the form of the first ventricular wave from simply + 

 to H — . But in view of the calculations to be made from the relative 

 amplitudes of the left and right records, I thought it necessary to re-try this 

 point in order to learn whether alterations of position great or slight cause 

 alterations of amplitude. I found that slight alterations are negligible, 

 but that great alterations, such as from standing to sitting, and lying either 

 on the back or on the face, or on one or other side, alter the amplitude and 

 the angle. I have therefore taken all observations from persons in the most 

 convenient position, i.e. sitting. 



The effect of considerable alterations of position is evident from the 

 following observation, in which the transverse, right and left lateral records 

 were taken of the subject B. 0. B. in the standing, sitting, and lying positions. 

 The points that come out most clearly on review of this group of records are 

 that lying on the left side as compared with lying on the right side diminishes 

 the angle «, as shown by increase of the left lateral spike and diminution of 

 the transverse spike. This alteration is also brought about by muscular 

 exercise {vide infra), and the reverse alteration, viz., increase of the angle «, is 

 caused by distension of the stomach. 



B. 0. B. (Feb. 26, 1913). 





Pulse 

 frequency. 



Transverse. 



E. lat. 



L. lat. 



a* 













Insp. Exp. 





74 



14 



14 



7-5 



31 (29 45) 



Sitting 



64 



15 



14 



5 



43 (40 53) 



Lying on back 



62 



15 



18 



7-5 



40 (39 50) 



Lying on right side... 



62 



17 



18 



5 



48 (42 50) 



Lying on left side ... 



60 



11 



16 



10 



25 (25 27) 



* The values of o given in parentheses are the approximate inspiratory and expiratory 

 numbers calculated from maximal and minimal values of the E and L spikes. 



