Sect. XIV. 2. a. OF IDEAS. 81 



It is hence, that we are very flow in acquiring our tangible 

 ideas, and very flow in recollecting them ; for if I now think of 

 the tangible idea of a cube, that is, if I think of its figure, and 

 of the folidity of every part of that figure, I muft conceive my- 

 felf as palling my fingers over it, and feem in fome meafure to 

 feel the idea, as I formerly did the imprefiion, at the ends of 

 them, and am thus very flow in distinctly recollecting it. 



When a body comprefles any part of our fenfe of touch, what 

 happens ? Firfl, this part of our fenforium undergoes a mechan- 

 ical compreffion, which is termed a itimulus ; fecondly, an idea, 

 or contraction of a part of the organ of fenfe is excited ; third- 

 ly, a motion of the central parts, or of the whole fenforium, 

 which is termed fenfation, is produced ; and thefe three coniti- 

 tute the perception of folidity. 



2. Of Figure, Motion, Time, Place, Space, Number. 



No one will deny, that the medulla of the brain and nerves 



has a certain figure ; which, as it is difFufed through nearly the 



whole of the body, mutt have nearly the figure of that body. 



Now it follows, that the fpirit of animation, or living principle, 



as it occupies this medulla, and no other part, (which is evinced 



by a great variety of cruel experiments on living animals^) it 



follows, that this fpirit of animation has alfo the fame figure as 



the medulla above defcribed. I appeal to common fenfe ! the 



fpirit of animation acts, Where does it act ? It acts wherever 



there is the medulla above mentioned ; and that whether the 



limb is yet joined to a living animal, or whether it be recently 



detached from it •, as the heart of a viper or frog will renew its 



contractions, when pricked with a pin, for many minutes of time 



after its exfection from the body. — Does it act any where elfe ? 



— No j then it certainly exifls in this part of fpace, and no 



where elfe ; that is, it hath figure ; namely, the figure of the 



nervous fyftem, which is nearly the figure of the body. When 



the idea of folidity is excited, as above explained, a part of the 



extenfive organ of touch is comprefTed by fome external body, 



and this part of the fenforium fo comprefTed exactly refembles 



?n figure the figure of the body that comprefTed it. Hence, when 



we acquire the idea of folidity, we acquire at the fame time the 



idea of figure ; and this idea of figure, or motion of a part of 



the organ of touch, exactly refembles in its figure the figure of 



the body that occafions it ; and thus exactly acquaints us with 



this property of the external world. 



Now, as the whole univerfe with all its parts pofiefles a cer- 

 tain form or figure, if &ny part of it moves, that form or figurf 

 Vol, I.' M of 



