182 THE SECRETIONS: 



during disease, principally in consequence of the diminution of 

 the chloride of sodium, which, however, is by no means one of 

 the most important of the saline constituents, and whose weight 

 may be determined in the manner described in page 140. It 

 is different, however, with the alkaline phosphates and sulphates, 

 which (more especially the sulphate of potash,) appear to fluc- 

 tuate considerably in disease. 



We may readily be convinced of the presence or of the total 

 absence of the aforesaid salts in urine which has become modi- 

 fied by disease, by the application of certain tests, or by the 

 methods which have been enumerated in page 130, under 

 9, 10, and 11; indeed the practised experimenter will be 

 able to judge from the specific gravity whether there is any 

 decided increase or diminution in the amount of the fixed alka- 

 line salts. 



As, however, it is of importance to know the exact amount 

 of the alkaline sulphates and phosphates in certain diseases, we 

 must adopt the method described in page 140, and determine 

 the relation of these salts to the solid residue. 



7. Increase of mucus. 



In catarrhal affections of the bladder the amount of mucus 

 in the urine is often very much increased. The urine in these 

 cases is acid or neutral, but frequently exhibits a strong ten- 

 dency to become ammoniacal in a short time. The colour is 

 usually unaffected, and seldom higher than ordinary. If there 

 is a very large proportion of mucus in the urine, a diffuse sedi- 

 ment of a viscid consistence, and of a white, yellowish, or dirty 

 yellow colour, will separate itself. 



If the urine exhibits a strong tendency to the formation of 

 ammonia, the mucus will become very tough, and almost thready. 

 The supernatant fluid is somewhat turbid, but heat induces no 

 coagulation unless albumen be present. 



The mucus may be recognized under the microscope by the 

 peculiar mucus- granules, which are usually rather larger and 

 less granular than those from the mucous membrane of the 

 lungs or nose. 



I have represented the mucus of the bladder, as it occurs in 

 certain pathological states, in fig. 31 a. 



