Vital and Physical Motion. 1 4 1 



shape of the comparatively non-expansible coat, acts 

 upon the contents in the same way as that in 

 which the shape of the tube of the thermometer 

 acts upon the column of mercury within it, or rather as 

 that in which the fine tube of the last new form of elec- 

 trometer is seen, under the microscope, to cause the 

 thread of mercury within it to lengthen or shorten as 

 the charge imparted to it rises of falls. It is that the 

 failure of this charge, which may be brought about by 

 failure in the due supply of oxygen, and in various 

 other ways, is attended by the development of 

 instantaneous currents of high tension, and that these 

 currents, by traversing the muscle, suddenly discharge 

 the remains of the charge, and so bring about 

 muscular -contraction. It is that this contraction is 

 brought about, not because a vital property of irrita- 

 bility has been roused or stimulated into action, but 

 simply because the discharge has removed for a moment 

 the charge which previously counteracted the action of 

 the attractive force or forces inherent in the physical 

 constitution of the muscular molecules. Nor is it to be 

 objected that the electricity -of the muscle is too feeble 

 to produce these results, for it may be that the electro- 

 motive action of muscle is .proportionate to the number 

 of electromotive elements (fibres or cells) in the muscle, 

 and that both charge and discharge are masked, the one 

 by being expended in the production of muscular elon- 

 gation, the other by being short-circuited within the 

 body. Nay, it is quite conceivable that the instan- 

 taneous currents of high tension which produce contrac- 

 tion would prove to be as powerful as those of the 

 Torpedo if they were not so short-circuited. And all 

 that is said of the action of the natural electricity of the 

 muscle is more than borne out by what is said of the 



