MUSCLES, NERVES, AND ELECTRICAL ORGANS. 177 



depends on the fact that the deflections are reduced. The galvano- 

 meter is so graduated that the relative rotating moment of the 

 bobbin was known for each 5 mm. of distance. In proportion to 

 the strength of the current the galvanometer bobbin was placed 

 at such distance from the mirror that it produced a suitable de- 

 flection A. Suppose m to be the relative moment for 20 mm. 

 distance of bobbin, m' the moment for the distance chosen each 



time, the reduced deflection A f = A ,. With the strongest cur- 



m 



rents were obtained reduced deflections of nearly 10,000 divisions 

 of the scale (see Sect. 6). In the numbers in row P of the table 

 the great imperfection attaching to these experiments notwithstand- 

 ing all my trouble, is seen. From the time of closure 4" '-636 

 onwards the collective deflections through the primary current 

 should have been the same. They vary in a ratio of 100 : 180, 

 partly from the impossibility of making the resistance of the 

 muscles and the wedge-shaped pads with their clay tips the same 

 size in several consecutive experiments, and (for this explanation 

 is hardly sufficient) partly on other unknown grounds. The 

 increase of the strength of the current, when the closure lasts one 

 minute or more, arises from the warming of the pads, of their edges, 

 and of the muscles themselves. With greater strength and longer 

 continuance of the current, this action is more than balanced by 

 external secondary resistance at the point where the current enters 

 the muscle. The polarisation after i' closure was so constant that 

 after a short time of opening the battery circuit the galvanometer 

 circuit could be closed without perceptibly altering the condition of 

 polarisation, so that it was unnecessary to use a new preparation 

 (p. 169). 



8. Graphic representation of the Polarisation curves in relation 

 to the time of closure ; Discussion of the same. 



However incomplete these experiments may be, a number of im- 

 portant conclusions may be drawn from them. The subjoined Fig. 5 

 shows shortly the general course of the phenomenon. Let T be the 

 time of closure, A the density of the primary current, + s the 

 strength of the secondary electromotive action, then the plane seen 

 in perspective like a boarded floor, is the ^-A-plane. At the points 

 of this plane corresponding to the given times of closure and the given 

 densities of current, the secondary actions are set off parallel to the 



