LIVING TOEPEDOS IN BERLIN. 491 



at ' physiological/ With the springs I and 2 on roller I, 9 on 

 roller II, every revolution between uprights C and D l gave two 

 equal and opposite extra currents of unbearable strength when 

 tested subjectively by the handles. The switch was connected with 

 the terminals of the coils of the machine, instead of with the 

 terminals of the induced circuit of the inductorium. As the switch 

 performed its to and fro motion whilst the machine was working, 

 the polarising effect of a series of really congruent alternating 

 currents on the organ could be studied. Although the action of the 

 machine at a distance upon the galvanometer could not be affected 

 by the movement of the switch, inasmuch as the armature was 

 constantly rotating, special care was taken to ascertain that no 

 change actually took place. 



I employed the i" and the l" ' disk of the polarisation switch 

 in succession, and I also tetanised for 30", 45", 120" by the watch. 

 The result was very uniform. Whether the terminals of the rotating 

 coils were connected with the dorsal or ventral surface of the 

 preparations, and whatever might be the duration of the tetanus in 

 fresh preparations, I could detect nothing but absolutely positive 

 polarisation, of such strength that with 5> turns at a distance of 

 30 mm. from the magnet, and with e = n, the scale disappeared from 

 the field of view. It then became more and more feeble, so that 

 with some preparations the action was very weak even from the 

 first. Never was it absolutely negative. The only difference, which 

 seemed to follow on longer duration of the tetanus, was in regard of 

 the persistence of the homodromous polarisation. It disappeared 

 the more quickly as the tetanising was continued for a longer time. 



It was astonishing how the organ preparations sustained such 

 powerful shocks, for no arrangement was made for their gradation ; 

 it seemed as if they were accustomed, in virtue of their function, to 

 impart such shocks to themselves. 



It is not difficult to understand the results on tetanising with 

 congruent alternating currents. First it is clear, that, as soon as 

 congruent shocks succeed each other in alternating direction and at 

 equal intervals, the reversal of the connections of the machine with 

 the preparations is illusory, and in truth produces no change. In 

 both arrangements, one is concerned with a similarly constituted 



that both their similar ends are connected together, and they then form a wire of 

 double thickness and half length. In the former case, the physiological effects are 

 the stronger, and the pachytrope is then said to be ' at physiological.' Tr.] 



1 Comp. the drawing in Poggendorff's Annalen, etc., 1842, vol. Ivi. Plate ii. Fig. i. 



