INDUCED ELECTEICITY. 27 



of equal strength, was limited in its action to the paralysed muscles 

 only. 



It has, therefore, been shown by the foregoing : — 



1. That the current of the first helix excites most acutely the 

 sensibility of certain subcutaneous organs ; the nerves, the muscles 

 (proportionately increasing their contractility), the rectum, tlie 

 bladder, the testes, the epididymis, and the spermatic cord. 



2. That the current of the second helix acts most powerfully 

 upon the cutaneous sensibility, upon the sensibility of the retina, 

 and penetrates most deeply into the tissues. 



F. — Theories of the differential jihysiological jproperties. 



Whatever be the cause of the differences observed in the physio- 

 logical properties of the currents of the two helices in every 

 double-induction apparatus, differences observed in varying degrees 

 in different instruments, according to the varieties in diameter and 

 relative length of their coils, it is incontestable that these pro- 

 perties, so important physiologically and therapeutically, and 

 which cannot be combined in a single helix, — it is incontestable, I 

 repeat, that these properties are not physiologically identical. It 

 is this that I mean to express by saying, apart from any physical 

 theory, that the currents of the first, and of the second helix possess 

 different physiological properties. 



With regard to the physical theory of these differences, esteeming 

 myself fortunate to have pointed out facts of such great practical 

 importance, that had previously escaped observation, I prefer leaving 

 their explanation to others, to physicists, more able than myself to 

 deal with them. In a communication addressed,^ in 1856, to the 

 Academy of Medicine, upon certain new physiological properties of 

 induced currents, I confined myself to expressing an opinion that 

 there was some connection between the degree of tension of the 

 currents, and their power to penetrate deeply beneath the skin. 

 If I did not attempt to explain also the physical causes of the 

 other differences, it was not for want of experimental inquiry into 

 the subject.^ 



* DuohenuG", Note sur quelques pro- \ in the text, we measure their physio- 



prle'tes cliffe'reutielles des courants cVinduc 

 tion de premier ef de secmide ordre ( Bull, 

 de VAcad. de Me'd., 18 Mars 1856, t. xxi. 

 p. 538). See also Rapport de M. Bouvier 

 (ibid., p. 671). 



8 The following experiment will show 

 that the currents of the first and of the 

 second helices possess different degrees 



logical power anew, after causing them 

 to traverse a portion of distilled water 

 in a glass tube, it will be found that the 

 current of the first helix is much more 

 weakened than that of the second. When 

 my most powerful induction instrument 

 is in action at its highest grade, and its 

 two currents are equalised, the current 



of tension. If, after having equalised of the first order ceases to be ])erceptible 

 the two currents in the manner described after having passed through distilled 



