62 THIRD KEPORT — 1833. 



cular system. Thus the vohintary muscles in all their natural 

 and sympathetic contractions receive the stimulant impulse of 

 volition through the medium of nerve ; and though the mode, 

 in vv'hich the motive impression is communicated to the invo- 

 luntary muscles, is still matter of controversy, there seems suffi- 

 cient evidence* to sanction the conclusion that nerve is in this 

 case also the channel of transmission ; — " that the immediate 

 antecedent of the contraction of the muscular fibre is univer- 

 sally a change in the ultimate nervous filament distributed to 

 that fibre." If this be correct, the physiological history of 

 muscle cannot be rendered complete without reference to that 

 of nerve. 



In the higher manifestations of life, nervous matter is in- 

 vested with the most eminently vital attributes. It is the ex- 

 clusive seat of the various modes of sensation, and of all the 

 intellectual operations; or, rather, it is the point of ti'ansition, 

 where the physical conditions of the organs, which are induced 

 by external objects, pass into states of mind, becoming per- 

 ceptions ; and where the mental act of volition first impresses 

 a change on living matter. These two offices of conducting 

 motive impressions from the central seat of the will to the mus- 

 cles, and of propagating sensations from the surface of the body 

 and the external oi'gans of sense to the sensorium commune, 

 have been of late years shown to reside in distinct portions of 

 nervous substance. 



The honour of this discovei'y, doubtless the most important 

 accession to physiological knowledge since the time of Harvey, 

 belongs exclusively to Sir Charles Bell. It constitutes, more- 

 over, only a part of the new truths, which his researches have 

 unveiled, regarding the general laws of nervous action, and the 

 offices of individual nerves. His successive experiments on 

 function, guided always by strong anatomical analogies in struc- 

 ture, in origin, or in distribution, have led to the entire remo- 

 delling of nervous physiology, and to the formation of a system 

 of arrangement, based on essential affinities and on parity of 

 intimate composition, instead of on apparent sequence or prox- 

 imity of origin. Among the continental anatomists, MM. Ma- 

 gendie and Flourens have contributed most largely to our 

 knowledge of this part of physiology ; the former by repeating 

 and confirming the experiments of Bell, as well as by various 

 original inquiries ; the latter by his important researches into 

 the vital offices of the brain and its appendages. Much light, 



* See " A Critical and Experimental Enqniry into the Relations subsisting 

 between Nerve and Muscle," in the 37th vol. of the Edinbiirr//i Medical and 

 Surgical Journal. 



