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think tolerably decisive. In the bone-ear tlr, 

 which is held in solution by the free acid of urine, 

 I found, as in the bones, fluate of lime, and by a 

 comparison with the composition of the blood, it 

 appeared, that the kidneys, in the formation of 

 urine, oxidate a portion of the more remote con- 

 stituent parts of the blood, and produce several 

 acids, alkalies and earths, which were either not 

 found in the blood before, or existed in it only in a 

 smaller quantity, Thus, for instance, I found in 

 the urine a considerable quantity of sulphuric and 

 phosphoric acid, the former of which is not dis- 

 cernible in the blood, and the latter only in a 

 very minute quantity. The portion of earthy 

 and alkaline salts, which urine contains, is also 

 very considerable, whereas in the blood it is but 

 small. The different sediments, which the urine 

 precipitates whilst cooling-, I found to be either 

 solely the mucus of the bladder, which is always 

 present in urine, partly suspended, and partly dis- 

 solved, or a combination of this mucus with the 

 uric acid ; but it does ^ot contain earthy phos- 

 phates. I have endeavoured to show the neces- 

 sity of making a distinction between the me- 

 chanical sediment, which is abundant in the ca- 

 tarrhus vesicse, and comes from the bladder, and 

 that, which takes place when the bone-eartk is 



