io Dr. Fordyce’s Lediure 
and febaceous matter, which every where covers the fcarf 
ikin ; under this lies the fcarf ikin, which the infuiion can 
hardly be conceived to come at ; if it did, the fcarf ikin we 
know is perfectly impenetrable to fuch a fluid ; it can there- 
fore never touch the Ikin, in which it excites inflammation, 
and on which it therefore ails at a diflance, and excites mo- 
tion, which no one can fufpeit to come through the nerves : 
nor is there any motion through the mucus and fcarf Ikin, of 
any other kind than would arife if an infufion of any other 
infeil had been applied, which had no power of exciting 
inflammation. ~ * 
From what has been faid we may conclude, that when a 
flimulus has been applied fo as to excite motion in a diftant 
part, no motion whatever takes place in the nerves, or is com- 
municated by them from the part to which the flimulus is 
applied to the moving part. 
I need not draw your attention to another propofuion, viz, 
that when a flimulus is applied to a diflan t part, fo as to pro- 
duce motion, it often happens, that the flimulating matter is 
not carried by the blood-veflels, or otherwife, to the moving 
part. This propofition has often been demonflrated, and is 
well known. 
All the original power exerted by any of the moving parts 
confifts in a power of particles coming nearer one another ; for 
every mufcle or fibre becomes fhorter when it ads ; or, in 
other words, contrails ; and every other moving part in like 
manner contrails when in aition. It is true, that there are 
many contrivances to make the contrailion. have great effcil in 
producing motion, force being never fpared for conveniency, 
as my friend Mr. Hunter has, 1 believe, already fet forth to 
my learned audience : but, neverthelefs, it is clear from every 
3 experiment 
