MUCINURIA. 195 



MUCINUBIA. 



Both normal and pathological urine often contain a 

 substance which, although similar to true mucin, yet dif- 

 fers from it in many respects. On account of this re- 

 semblance it is often called urinary mucin. The latest in- 

 vestigations indicate that it is a nucleoalbumin. In nor- 

 mal urine it appears after standing as a light, fleecy cloud 

 in the middle of the liquid. Its origin is the mucous mem- 

 brane, principally that of the bladder, ureter, and vagina. 

 In small amounts it has no special significance. In catar- 

 rhal inflammation of the bladder it is abundant. In cys- 

 titis and pyelitis it may give the urine a gelatinous appear- 

 ance. Mucin is also increased in febrile conditions, as well 

 as in nephritis. 



Urinary mucin is precipitated from its solution by 

 alcohol or dilute acetic acid without heating. It may be 

 precipitated by very dilute mineral acids, but dissolves in 

 excess. After precipitation by acids it is soluble in alka- 

 lies. Since nucleoalbumins, like the mucin of urine, are 

 composed of an albuminous substance with a nuclein, they 

 give most of the reactions of the albumins, such as those 

 with potassium ferrocyanid, picric acid, the biuret test, 

 etc. Care is necessary, therefore, to avoid confounding 

 urinary mucin with small quantites of albumin. They 

 can be differentiated by the fact that the mucin is precipi- 

 tated in the cold by acetic acid even after the urine has 

 been diluted with water, while albumin is not. 



411. Dilute normal urine with its own volume of 

 water, acidify a small beakerful with acetic acid and allow 

 to stand until the mucin has separated. Filter and wash 

 with water. 



