On Oxalic Acid. $9 



bones, as the bone must become soft before it swells ; which 

 softness is owing to defect of the secretion of phosphorated 

 calcareous earth. The swelling of the bone compresses a 

 part of the brain, called the spinal marrow, within the cavity 

 of the back- bones; and in consequence the lower limbs be- 

 come paralytic, attended sometimes with difficulty of empty- 

 ing the bladder and rectum. 



M. M. Issues put on each side of the prominent bone are 

 of 2jeat effect, I suppose, by their stimulus; which excites 

 into action more of the sensorial powers of irritation and 

 sensation, and thus gives greater activity to the vascular sy- 

 stem in their vicinity. The methods recommended rn distor- 

 tion of the spine are also to be attended to. 

 [To be continued.] 



V. On Oxalic Acid. By Thomas Thomson, M. D. 

 F.R.S. Ed. Communicated by Charles Hatchett., 

 Esq., F.R.S. 



[Concluded from vol. xxxi. p. 25S.] 



IV. Composition of Oxalic Acid. 



JL he knowledge of the relative weights of the elements 

 which compose oxalic acid, though of importance, is not 

 sufficient to convey a clear idea of this compound, and in. 

 what respect it differs from tartaric acid, alcohol, sugar, and 

 various other bodies possessing very different properties, 

 though composed of the very same elements in different pro- 

 portions. 



It has been ascertained, by numerous and decisive expe- 

 riments,, that elementary bodies always enter into combina- 

 tions in determinate proportions, which may be represented 

 by numbers. For example, the numbers which correspond 

 to the four elements, oxygen, azote, carbon, and hydrogen, 

 are the following : 



Oxygen 6 



Azote - 5 



Carbon - 4*5 



Hydrogen 1 



C 4 Now j 



