102 FOURTH REPORT — 1834. 



sive of muscular motion, wliich exemplify themselves by tension 

 and relaxation of parts,ancl which he called tonic motions, — those, 

 also, he considered as effects of the soul's power. He rejected 

 the laws of physics or of chemistry, and the discoveries of ana- 

 tomy, as throwing the least light upon the fundamental processes 

 by which the corporeal manifestations are effected. He considered 

 that the soul has no seat in any particular part, but that it is co- 

 extensive with the body itself; that it perceives in the organs of 

 sense, and operates in the muscles, independently of any con- 

 nexion with the brain*. Had not Stahl failed to distinguish be- 

 tween the manifestations of his vital principle, according as it ex- 

 emplifies itself by means of those organs which it has formed, — 

 had he not described it as the ' rational soul', — his system, con- 

 firmed by subsequent observation as to the general principle 

 upon which it would then have been founded, — that of vital pro- 

 perties inherent in the several tissues, — could scarcely have been 

 justly censured. It was received in a modified form by many of 

 those whom T have instanced (from the mode in which they ap- 

 plied it,) as disciples of other schools. In England it was de- 

 fended by Bryan Robinson, and by Meade, and gained much ce- 

 lebrity from the writings of Hartley, who assumed its principle 

 to explain the association of ideas. It was received also, in a 

 modified shape, by Sauvages in France, by Bonnet in Switzer- 

 land, by Whytt in Edinburgh. The latter taught that the soul 

 is the primary cause of all the motions observable in the body. 

 These he divided into three kinds : natural motions, depending 

 upon a gentle and equable supply of nervous influence (of which 

 the tension of the sphincters and the general tone of parts are 

 instances), and proceeding without the interference of the will or 

 of stimuli ; involuntary, excitable by stimuli affecting the 

 nerves (and he attempts to show that in all motions produced by 

 stimuli, whether in the muscles of the limbs or of the viscera, 

 the soul acts of necessity) ; voluntary motions, under the im- 

 mediate influence of the soulf. James Johnstone greatly modi- 

 fied this theory in England, but his opinions were not received 

 by his own countrymen. He also assumed a vital principle to 

 effect that which mechanical or chemical powers were obviously 

 iniabie to perform. He placed its principal seat in the brain, 

 thence to be propagated by the nerves, and pointed out an office 

 of the ganglia, (which, indeed, had been hinted at by Winslow 

 and Le Cat,) viz., that those organs which are supplied with 

 nerves from the ganglia, performing their motions independently 

 of the will, the ganglia are to "be considered as so many subsidiary 



• Thompson, op. cit. 



\ Whytt Oil the Fiial and Inooluntanj Motions, passim. 



