508 Dr. A. D. Waller. Various Inclinations of the [Mar. 6, 



repeated observations during the year 1887 and whose current-axis I then 

 estimated, or rather guessed, as forming an angle of 45° with the vertical line. 

 His normality was, of course, verified at the time. And I have been fortunate 

 enough a few days ago to obtain records of the four necessary leads from 

 which the angle of the current-axis can be calculated. It happens to come 

 out at the value of 45°, which in itself is, in my opinion, proof of normality. 

 And the photograph that was taken of this subject last week as compared 

 with the sketch of the same subject that was used as a class-diagram 27 years 

 ago is in itself sufficient proof of normality as to the state of the heart. 



In 1887 the idea occurred to me that it should be possible to utilise the 

 limbs as natural electrodes in relation with more or less opposed aspects 

 of the heart, and so to obtain information concerning the absolutely 

 intact organ. With the aid of Lippmann's capillary electrometer I surveyed 

 all the different pairs of leads that I could think of, and as the outcome of 

 this survey, divided the human body into two unequal parts by means of an 

 imaginary line or equator cutting at right angles a second imaginary 

 line or current-axis crossing the chest obliquely in the direction of the 

 anatomical axis of the heart — itself an imaginary or at least an indefinite 

 line. I figured the current-axis as forming an angle of 45° with the vertical 

 and taking the leads two by two I found that they fell into two sets which I 

 called " favourable " and " unfavourable." On review of these observations it 

 became apparent that in the " favourable " cases, i.e. those in which the 

 electric pulse was obvious, the two leads were on opposite sides of the 

 equator, while in the "unfavourable" cases, i.e. those in which little or no 

 pulse was visible, both leads were on the same side of the equator. I 

 ascertained by direct observation that of the six possible leads afforded by 

 the four extremities taken two by two, three are favourable (1, 2, 3) and 

 three unfavourable (4, 5, 6) as regards the demonstration of the electrical 

 pulse ; and that of the four possible leads from the extremities taken in 

 conjunction with the mouth, three are favourable (7, 8, 9) and only one 

 unfavourable (10).* 



Finally the proof of the relation between the normal obliquity of the heart 

 and favourable and unfavourable leads was completed by the investigation of 

 two cases of situs viscerum inversus where in correspondence with the reversed 

 obliquity of axis, the transverse effect between the two hands was observed 

 to be reversed ; the right superior and left lateral leads to be favourable ; 

 the left superior and right lateral to be unfavourable. 



* "Waller, " On the Electromotive Changes connected with the Beat of the Mammalian 

 Heart, and of the Human Heart in particular," ' Phil. Trans.,' 1889, p. 169. The principal 

 facts were demonstrated, in 1887, at the First Congress of Physiology, at Bale. 



