Electrical Axis of the Human Heart. 



61 



fluctuation produces in the mind of the observer a corresponding state of 

 indecision as to what value is to be taken for difference of potential during 

 the three to four hundredths of a second of the presystole while the chemical 

 and electrical changes preparatory to contraction are proceeding. 1 have 

 given much thought to such doubtful cases, and made many attempts to 

 synchronise fluctuating records and to calculate the fluctuating angle at 

 definite points during the initial period of systole, but without any satis- 

 factory result ; the fluctuations have proved to be too rapid to allow of any 

 satisfactory establishment of corresponding points in time between different 

 records, even when such records have been taken simultaneously. I have 

 therefore for the present abandoned the attempt, and taken for these 

 doubtful cases maximal and minimal values, whether positive or negative, 

 and calculated separate values of a from such values, duly noting, of course, 

 their doubtful character. An example in point is given in Part I at p. 520, 

 the case of Dr. E. 



I have not found it possible to make any satisfactory correction for 

 asynchronism between the initial and culminating points of the transverse 

 and lateral spikes, and have taken into formula only the values of the right 

 and left lateral (inferior) spikes, of which, according to my observations, the 

 asynchronism is so small as to be negligible.] 



Values of Vi in the several Leads at Different Values of the Axial Angle. 

 (Taken by direct readings of the model to the nearest millimetre.) 





I. 



Transverse. 



ill. 



Eight 

 inferior. 



III. 



Left 

 inferior. 



IV. 



Eight 

 superior. 



V. 



Left 

 superior. 



VI. 



Longitudinal. 



o 











100 



100 



50 -0 



50 



150 



10 



17 



107 



90 



40 -5 



58 



148 



20 



34 



111 



77 



30 -0 



64 



141 



30 



50 



111 



62 



18 -0 



68 



130 



40 



64 



109 



45 



6-0 



70 



115 



50 



77 



102 



26 



- 6-0 



70 



96 



60 



87 



93 



7 



-18 -0 



68 



75 



70 



94 



81 



-13 



-30 -0 



64 



51 



80 



98 



66 



-32 



-40 -5 



58 



26 



90 



100 



50 



-50 



-50 -0 



50 







