728 PHYSIOLOGICAL CHEMISTRY. 



Nucleo-albumin. If the ring occurring in Heller's test some dis- 

 tance above the place of contact becomes more distinct when the 

 urine is diluted, it is believed to be of protein origin, and has been 

 called nucleo-albumin, mucin, euglobulin, Morner's body, etc. Its 

 true nature is not yet known. The cloud produced by acetic acid 

 in the cold is believed to be due to the same body. As urates may 

 be precipitated in both of these methods, it is important to rule them 

 out by diluting the urine, when the precipitate due to urates will not 

 appear. True nucleo-albuminuria is rare. 



Blood. The presence of blood in urine manifests itself generally, 

 unless the amount be too slight, by a blood-red or brow r nish color 

 with a bluish, smoky, or greenish tint, and deposits a red or reddish- 

 brown sediment after standing. As a general rule, all constituents 

 of blood, including the corpuscles, are present (haematuria), but in 

 some cases only haemoglobin (methaemoglobin) is found (haemoglobin- 

 uria). 



The tests for blood depend either on the microscope, spectroscope, 

 or on chemical changes. By the microscope is examined the deposit 

 which forms on standing ; almost unaltered blood-corpuscles may be 

 found, or they may be much swollen, decolorized, and deformed. 



Haematuria is common and occurs in diseases of the kidney (acute 

 nephritis, stone, tuberculosis, trauma) ; similar conditions of the ure- 

 ters and bladder ; general conditions (malignant forms of smallpox, 

 malaria, etc. ; haemophilia). 



Haemoglobinuria occurs occasionally in severe fevers (scarlet fever, 

 yellow fever) ; after severe burns or exposure to cold ; in certain 

 poisonings (potassium chlorate, carbon monoxide). It is always pre- 

 ceded by haemoglobinaemia, i. 6., the presence of free haemoglobin in 

 the circulating blood. The spectroscope shows the absorption-bands 

 of the blood-pigments, for which see Fig. 72. 



Tests for blood in urine. 



1. Render alkaline with sodium hydroxide and boil. In the pres- 

 ence of blood coloring-matter the precipitate of phosphates produced 

 is colored red. In a urine containing other coloring-matters (bile- 

 pigments, etc.) the test may be misleading ; in such cases, filter off 

 the precipitate, wash, and dissolve it in acetic acid. In the presence 

 of blood-pigment the solution becomes red, but the color gradually 

 disappears on exposure to air. 



2. Allow a mixture of freshly prepared tincture of guaiacum and 



