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 
