[ 188 ] 
examination, it has been found, either 
that they were repugnant with the ftruc- 
ture of the mufcles, or the laws of me¬ 
chanics, or that they repofed upon arbi¬ 
trary data. 
Baron Haller fetting off from a known 
fadt, that is to fay, from the approxima¬ 
tion which takes place betwixt the ele¬ 
ments of the fibres during the moment of 
mufcular contraction, attributes contrac¬ 
tion itfelf to an increafe of the power of 
attraction which refides, as he exprefTes 
himfelf, in the very nature of the moving 
fibre. 
Dr. Fordyce has taken up the fame doc¬ 
trine, and it has likewife been embraced 
by Dr. Blane. This appears alfo to have 
been the opinion of Sir Ifaac Newton. 
Of the Nervous Force. 
When we make ufe of the term attrac¬ 
tion, we only exp refs an effect.- This ef¬ 
fect 
