The extension of this substance, not only with tta 

 skin round the whole body, but also round every vis. 

 cus or organ, and round every individual moving fibre 

 or vessel of them, into the cavities of the bones, and 

 even the substance of the brain and its medulla, is a 

 modern and wonderful discovery. This substance in 

 its ultimate state being composed of simple membranes,, 

 when compacted and convoluted, gives birth- to the 

 least or most simple vessels, which again reflected 

 through plates of the same substance compacted toge- 

 ther, make compound and vascular membranes:, to the* 

 consideration of which we next proceed. 



Out of this cellular substance compacted by a eon* 

 cretion of the membranous plates or partitions, and 

 pressed together by the force of the incumbent mus- 

 cles, and distending fluids, arise other broad and flat 

 plates or skins in various parts of the body ; which 

 being generally disposed in one and the same direction, 

 seem to have a better right to the name of membrane 

 than the former; and these being convoluted into 

 cones and cylinders, pervaded by a flux of some juice 

 or liquors brought to them, put on the name of ves- 

 sels, or else being extended round some space that is in 

 a plane, parallel to itself, we call it a tunic or coat. 



This cellular substance in the human body, is found 

 throughout the whole ; wherever any vessel or mov. 

 ing muscular fibre can be traced, and this without the 

 least exception, that I know of, in any part whatever. 

 But so far as ever we can trace, it hardly ever admits 

 of any iat into the cells; which are rather moistened 

 by a watry vapour, somewhat oily, exhaled out of 

 the arteries and received again into the veins. 



Its plates or scales are still more loose and open 

 where it divides the muscles and all their iibres (even 

 to the ultimate fibre ; and likewise where it surrounds 

 and sustains the least vessels with their free motion. 

 That within the cavities of the bones is also made up 

 of bony plates, with membranous ones intermixed ; 

 and lastly, it is the most loose and open of all> round 



