APPENDIX. 



695 



of its own outgoing energy." The feeling of 'expended energy ' 

 by which we obtain our ideas of resistance and of an external 

 world is not contained in, or an appanage of, the volitional act, 

 ** but is derived, through impressions emanating from the moving 

 organs themselves." Our perceptions of 'resistance 'and of 'weight* 

 are, in fact, " partly made up of tactile impressions, partly of 

 passive sensations emanating from our muscles and joints, and of 



inferences founded upon these We experience certain 



feelings of pressure, combined with certain sensations in the 

 muscles and in the joints, and we gradually come to associate 

 certain combinations of these with the sensations produced by 

 handling certain standard weights." If the term * muscular sense ' 

 is not to be applied to the passive sensibilities of muscle, then it 

 must be restricted to mere 'unconscious' impressions, which may, 

 perhaps, pass upwards from spmal motor ce^itres to the brain by a 

 special set of fibres (see p. 699, note). Such an endowment would, 

 in that case, have to be regarded as " an unconscious organic guide 

 in the performance of voluntary movements," and for the existence 

 of some such guide, evidence is not altogether wanting. It would 

 also, in all probability, supply the guiding sensations necessary 

 during the continuance of automatic movements. 



If we attempt to classify the views (which have been above set 

 forth or referred to in mere order of time), as to the modes by which 

 we apprehend different degrees of resistance and 'iceight, they may 

 be ranged as follows : — 



1. Estimation of Will-force (through a ao-called 'loo mo- 

 tive faculty ') anterior to aud independent of sensations from 

 the moviijg members. Scaliger and Wundt. 



2. By a "sense of expended energy" which is "a con- 

 comitant of the outgoing current "—that is, by a sensory 

 revelation resulting from the activity of motor centres, 

 nerves and muscles. (This view, which is allied to the last, 

 differs from it by the added supposition, that the appreci- 

 ation of weight ur resistance requires more than the activity 

 of the volitional centre, and can take place only on con 

 dition that the motor incitation is not stopped by paralyzing 

 or o.her lesions, but goes on to evoke the activity of the 

 motor neives and muscles with which the volitional centre 

 is in relation.) Bain. 



3. By ingoing currents or impressions from the muscles, 

 conveyed back to tbe volitional centres by the uioror 

 nerves themselves. (Mcording t<j this view, motor centres 

 and n rves would be coincic ently or in immediately succea 

 give increments of time enga^-ed with outgoing and with in 

 going c urrenta. ) Lewes, 



Throug-h. 



Motor 

 Centres. 



