44 THE BUTYRIC ACID GROUP. 



animal organism, at least in large quantities. It only occurs in 

 the latter in combination with lime, never being present in suffi- 

 cient quantity to combine with the alkalies as well as with lime. 

 Moreover it is much more frequently met with in pathological 

 than in physiological conditions. 



It is in the urine that the presence of oxalate of lime has been 

 most frequently observed; it was for a long time regarded as a mor- 

 bid product in this fluid, but independently of the circumstance 

 that this body is constantly present, together with carbonate of 

 lime, in the urine of herbivorous animals, it has frequently been 

 found in normal human urine by myself,* Hofle,t and others. 



In examining microscopically the morning urine of healthy men 

 I have frequently discovered isolated crystals of oxalate of lime ; 

 this is not, however, always the case : and further, the oxalate of 

 lime recognisable in such cases by the microscope is not all that is 

 contained in the urine, for it forms in larger quantities after some 

 time, and during the acid urinary fermentation so admirably 

 described by Scherer. After allowing morning urine to stand for 

 a considerable time we often find a great many of these crystals, 

 when the perfectly fresh urine presented no trace of them. The 

 following is an excellent mode of demonstrating the existence of 

 oxalate of lime in normal urine. If it be winter we must expose 

 fresh urine out of doors till it freezes ; in this process, as in the 

 freezing of wine and vinegar, a great part of the water crystallises 

 in a comparatively pure state, and after its removal we obtain a 

 concentrated saline solution in which microscopic crystals of oxalate 

 of lime may be discovered. That oxalate of lime is at first actually 

 held in solution in filtered urine, and that it does not, as C. Schmidt 

 supposes, proceed from the mucus of the bladder, is a view which 

 is supported by the experiment which I have often repeated, that in 

 urine, which after thoroughly cooling was freed from its mucus and 

 urate of soda by filtration, the most distinct crystals of oxalate of 

 lime might after a time be recognised, while no traces of them could 

 either previously be detected in the mucus of the fresh urine, or found 

 after the residue on the filter had been for some time in contact 

 with water. The oxalate of lime, with a few crystals of uric acid, 

 does not separate from filtered urine until after it has stood for some 

 time. We may very easily convince ourselves that oxalate of lime 

 is present in a state of solution, by extracting the solid residue of 

 filtered urine with not too concentrated spirit, and agitating the 

 spirituous extract with ether ; after the extraction with ether, there 



* Wagner's Handworterbuch der Physiologic, Bd. 2, S. 6. 



t Chemie und Mikroskop am Krankenbette. Erlangen, 1848 S. 385. 



