MEMOIR OF BARON HALLER. 29 



to effect a revolution in the character of the science, 

 by appealing in all possible cases to direct experi- 

 ment. At the period we now refer to, the doctrines 

 of the circulation of the animal spirits, effected 

 through the agency of the dura mater, which trans- 

 mitted its prolongations to the very extremities of the 

 frame, and there constituted the seat of the faculty of 

 sensation, were prevalent and almost uncontroverted 

 dogmata, utterly at variance with the truth. Haller 

 impugned and overturned these doctrines ; and thus 

 merited the high commendation due to those who 

 set aside false doctrine. Both Pacchioni and Bag- 

 livi maintained that the dura mater was muscular, 

 and transmitted the vital fluid with a force not less 

 than that which was exercised by the heart itself. 

 Haller, on the contrary, demonstrated by experiment 

 and otherwise, that the dura mater differs in no 

 essential particular from the other cellular mem- 

 branes of the body; that it was in no degree 

 muscular ; that it did not supply a sheath to the 

 nerves, which, on the contrary, had their own proper 

 coverings wholly distinct from the dura mater: he 

 demonstrated that this membrane had no apparent 

 sensibility whatever, and therefore, from this con- 

 sideration alone, could not be the seat of sensation 

 and motion. In his own words" I inquired if the 

 dura mater were irritable ; if it contracts, and so 

 acts as a muscle. This enters essentially into Bag- 

 livi's system, and I plainly aver the contrary. In 

 most animals the dura mater is closely attached to 

 the bone, and if detached from it, it always is void 



