NATURK or THE IXTEKV E RTEB R AL SUBSTANCE. 20^ 



out with SO much velocity, that it rose to the height of four 



feet. 



At the end of twelve days, I liad an oppovtiinitv of exa- Coagulates af- 

 c 1 ' ■ 1 • 1 i" • • „ terc.eath. 



mining a portion o! the spine, tne intervertebral joints ot 



which were preserved entire; upon sawing through two of 

 the vertebrae, a fluid" was met with, of the consistence of li- 

 quid jelly with clots of different sizes floating in it, so that 

 in eight days a considerable tendency to coagulation had 

 taken place, although the fluid was entirely excluded ffom 

 the external air. 



The form of the cavity, thus exposed by a longitudinal Cavity con- 

 section being made of it, is nearly spherical, capable of con- ^^'"'"S it- 

 taiciing three pints of liquid ; the lateral parts are ligamen- 

 tous and elastic, uniting together the edges of the concave 

 surfaces of the tv^-o contiguous vertebrse. When the liquid 

 is evacuated, the elasticity of the lateral ligninents brings 

 the ends of the vertebrae within an inch and half of each 

 other ; in this state the inner layers of the ligaments, which 

 are less tirra in texture than the outer, project into the ca- 

 vity, and may be mistaken for a part of its natural contents; 

 this portion when soaked in water swells out to a consider- 

 able size, the water readily insinuating itself between the 

 membranous layers of which it is composed. 



The whole thickness of the lateral ligaments is about one Lateral liga- 

 inch, the external half of which is compact and elastic, the 

 other appears to possess a very slight degree of elasticity. 

 The appearance of the joint is shown in the annexed draw- 

 ing, and an account of the analysis of the fluid by Mr. W. 

 Brande forms a postscript to this paper. Every part of the 

 mechanism is formed on so large a scale, that it is rendered 

 conspicuous, and nothing is left to doubt or conjecture; the 

 -nature of the joint is different from every other that is met The jomf 

 with in animal bodies, and there are many circumstances 

 respecting it, which render it uncertain whether human in- 

 genuity can ever make any resemblance to it, that can be 

 applied to the purposes of rpechanics. 



These would have been sufficient grounds for bringing enables us to 

 this subject before the Society ; but there are others of still 'j-oJ^'mon prhi- 

 greater importance, which have induced me to make ft a pies oi tlie 

 separate communication; it enables us to explain the gene- spij^e"'*" ^ ^** 



Vol. XXV.— Mar. 1810. P, ral 



