620 



NATURE 



[Oct. 25, 1888 



The successful issue of the observations is so certain 

 that they can be best described in the form of directions 

 to a person who should be desirous of seeing them 

 for himself, followed by the prediction of what will be 

 observed by him. 



§ I. Two vessels of salt solution are to be pre- 

 pared, and connected with the capillary electrometer 

 by electrodes. The various extremities of the observer 

 are to be dipped into the salt solution, while the capillary 

 column is watched. Electrical variations, apparently 

 synchronous with the heart's pulse, will be observed with 

 certain combinations rather than with others, and the 

 results (on a normal person with the heart pointing to the 

 left) will be as follows : — 



Connect with electrometer — 



1. Left hand and right hand 



2. Left hand and left foot 



3. Left hand and right foot 



4. Right hand and left foot 



5. Right hand and right foot 



6. Right foot and left foot 



Electrical variations 

 Little or no variations 

 Little or no variations 

 Electrical variations 

 Electrical variations 

 No electrical variations 



will be apparent. 



Further observations may be made with the mouth used 

 as a leading-off point in connection with each of the four 

 extremities. To lead off from the mouth a silver electrode 

 coated with silver chloride is kept under the tongue. The 

 results will be as follows : — 



Connect with ehctrometer — - 



7. Mouth and left hand 



8. M iuth and right hand 



9. Mouth and left foot 

 o. Mouth and right foot 



Electrical variations 

 Little or no variations 

 Electrical variations 

 Electrical variations 



will be apparent. 



Finally, it is possible to add to the evidence obtained, 

 by using the rectum as a lead off by means of a silver 

 electrode. This, if tried, would give with 



11. Rectum and mouth 



12. Rectum andleft hand 



13. Rectum and right hand 



14. Rectum and left foot 



15. Rectum and right foot 



Electrical variations 

 Little or no variations 

 Electrical variations 

 Little or no variations 

 Little or no variations. 



These will have been the results ; the cases in which the 

 mode of leading off has been favourable to the production 



of electrical variations will be unmistakably distinguished 

 from those in which the mode of leading off has been 

 unfavourable. 



The explanation of these facts is most shortly given in 

 the diagram, c c is the axis of any current which must be 



produced if at any time the apex and base of the ventricles 

 differ in potential. 00 is the line of zero potential at 

 right angles to C C. 



a a a are equipotential lines round a supposed focus A. 

 b b b are equipotential lines round a supposed focus B. 

 Any lead off from two superficial points a a or b b is un- 

 favourable. Any lead off from two points a b is favourable 

 to the manifestation of electromotive differences originat- 

 ing at the heart. This will have been demonstrated by 

 the experiments directed to be made. 



§ II. On a quadruped (dog, cat, rabbit) the results 

 will come out somewhat differently. The heart occupies 

 an approximately median position, so that the asymmetry 

 observed on man does not hold good with the above- 

 named animals. In these the current axis will be along 

 a median longitudinal line ; the line of zero potential will 

 be at right angles to it, i.e. transverse. 



This can be verified by trial with very little trouble. A 

 quadruped is led off by the various extremities and 

 orifices immediately after death before the heart has 

 ceased to beat ; or a dog may be trained to stand quiet 

 with his feet in dishes of salt solution (I have a large 

 and well-disposed dog who will stand thus by the hour). 

 However the test be made, the results will come out as 

 follows : — 



Connect with electrometer — 



1. Left paw l and right paw 



2. Left paw and left foot 



3. Left paw and right foot 



4. Right paw and left foot 

 Kight paw and right foot 



Little or no electrical variations 

 Electrical variations 

 Electrical variations 

 Electrical variations 

 Electrical vacations 

 Little or no electrical variations 

 will be apparent. 



Extending the observations to mouth and rectum, the 

 results will be thus : — 



6. Right foot and left foot 



7. Mouth and left paw 



8. Mouth and right paw 



9. Mouth and left foot 



10. Mouth and right foot 



1 1 . Mouth and rectum 



12. Rectum and left paw 



13. Rectum and right paw 



14. Rectum and left foot 



15. Rectum and right foot 



Little or no electrical variations 

 Little or no electrical variations 

 Electrical variations 

 Electrical variations 

 Electrical variations 

 Electrical variations 

 hlectrical variations 

 Little or no electrical variations 

 Little or no electrical variations. 



§ III. Upon these two proofs may be piled a third proof 

 of the correctness of the facts and of their explanation. 

 Cases of situs viscerum inversus are to be found ; the 

 viscera of such people are situated as those of a normal 

 person seen in a mirror ; i.e. inter alia, the heart points to 

 the right. I have examined two such cases, with results 

 exactly as anticipated, viz. the favourable combinations, 4, 

 5, and 7, of a normal subject (§ I.) are unfavourable in the 

 case of situs inversus, while the unfavourable combina- 

 tions, 2, 3, and 8, are favourable. Combinations 1, 9, and 10 

 are favourable, and 6 is unfavourable in both cases, there 

 being the notable peculiarity as regards 1 that the varia- 

 tions are reversed in direction in each of the two cases. 

 The significance of this point will be obvious to the 

 reader who has followed the facts up to this point : in 

 both cases we have a favourable combination, but a 

 reversal of points a and b. 



§ IV. As regards the character and direction of each 

 cardiac variation, it will be found to be composed of two 

 phases, the first short, sharp, and difficult to read as 

 regards direction, the second comparatively prolonged 

 and easy to read. The second phase clearly indicates 

 negativity of the heart's base, the first phase less clearly 

 negativity of the heart's apex — facts which testify that the 

 contraction begins at the apex and ends at the base of 

 the ventricles. The auricular contraction does not affect 

 any electrometer I have used. 



1 "Paw" is used as an alt relation for anterior extremity ; "foot" for 

 posterior extremity. 



