98 LIFE AND ORGANISATION. 



nervous force acts; and by presuming, as indeed we are 

 compelled to do, that these diversities are often of a nature 

 to evade the most subtle research. The chemist and the 

 microscope have disclosed to us many marvellous secrets 

 of molecular aggregation ; but they have rarely, if ever, been 

 able to tell us of that ultimate structure, which at once de- 

 fines and fulfills the various functions of life. 



We have spoken of Electricity as the physical power most 

 nearly allied, so far as we yet know, to that acting through 

 the nervous system. We are not propounding here one of 

 the many vague hypotheses to which electricity, from its 

 striking and complex phenomena, has given birth ; but what 

 is a legitimate inference from the most exact and delicate 

 experiments. These, while leaving the fact of identity still 

 unproved, and many collateral questions yet unresolved, 

 have nevertheless disclosed such analogies and intimate 

 relations, as to make it probable that the forces in question 

 are at least mutually convertible, in the sense we have 

 already given to this phrase. Had we space for it, we might 

 relate some of those wonderful results derived from the ex- 

 periments of Du Bois Eaymond and Matteucci, which espe- 

 cially favour this interpretation. We may mention, as perhaps 

 more cogent in its conclusions than any other, one we have 

 ourselves often seen ; where a sudden and forcible contrac- 

 tion, by will) of the muscles of the forearm, evolves a current 

 of electricity capable of passing through two or three miles of 

 a helix coil, and creating power enough to deflect the needle 

 of a delicate galvanometer, 50 or 60 or 70, according to 

 the vigour of the muscular contraction. The inference here 

 seems direct and decisive; and it corresponds with other 

 conclusions from the experiments of Du Bois Raymond, as 

 to the uniform direction of the electrical currents pervading 

 all muscular fibres. Yet we are still short of that certainty 

 which science is rigid in requiring. We have reason to 



