URINE. 179 



in pathological conditions of the urine can only be ascertained 

 by the analytical proceedings described in pages 118 and 137. 



6. Increase or diminution of the fixed salts. 



The qualitative and quantitative variations occurring in the 

 mixture of the fixed salts of the urine in disease are deserving 

 of much attention. Some of these changes may be recognized 

 without difficulty. 



a. Increase or diminution of the earthy phosphates. 



There are certain diseased states of the system in which the 

 earthy phosphates are absolutely increased to a very marked 

 degree ; there are others, again, in which they decrease in an 

 extraordinary manner, or even altogether disappear. 



a. It is no very rare occurrence for the free acid of the urine 

 to become neutralized by the formation of ammonia, and the 

 urine thus becoming neutral or even alkaline, the earthy phos- 

 phates are precipitated. Urine in which these events occur 

 is most commonly light-coloured; sometimes, however, dark. 

 Blue litmus paper is not at all reddened by it, in fact red litmus 

 is usually rendered slightly blue, and in some cases a powerful 

 alkaline reaction is manifested. Generally speaking, the urine is 

 clear and slightly acid at the period of its emission, but in a 

 very short time it undergoes the change we have stated; a 

 change which also occurs in normal urine, but not till after the 

 lapse of several days. It becomes turbid, a film is formed on 

 the surface in which minute crystals may be frequently detected 

 with the naked eye. A sediment shortly begins to form, and 

 at the same time the inner surface of the glass which contains 

 the urine becomes covered with a stratum of salts ; at least I 

 have observed this to occur in several instances. Sediments of 

 this kind are sometimes scanty, sometimes very copious. I 

 have seen a case in which the sediment, which consisted almost 



in this pigment varies inversely with the degree of oxidation of the blood ; that its 

 formation is analogous to the formation of uric acid and urea ; that the carbon and 

 hydrogen contained in it do not increase in an equal ratio ; and that, finally, a long- 

 continued secretion of urine, rich in this colouring matter, usually induces anaemia 

 and emaciation. (Med. Times, Oct. 11, 1845.)] 



