466 A TEXTBOOK OF PHYSIOLOGY 



this to stand for twenty-four hours, the amount may be read off on 

 the graduations of the tube. The figures correspond to the number 

 of grammes of albumin present per litre. 



Normal urine yields a " mucus " on standing, which appears to 

 be a mixture of nucleo-protein and gluco-protein. This is derived 

 from the urinary tract. In catarrhal conditions of this, the amount 

 of mucus may be so much increased that a condition known as " mucin- 

 uria " is met with. A white precipitate, insoluble in excess, and 

 increased on boiling, is indicative of " mucin." The test often succeeds 

 better when the urine is previously diluted to half its strength with 

 water. 



Another abnormal condition of the urine sometimes met with is 

 due to the presence of proteoses in the urine. These appear in the 

 urine when disintegration of tissue is going on during an infective 

 disease e.g., in pneumonia, when an abscess known as empyema is 

 forming. A special form of proteosuria, known as myelopathic or 

 Bence-Jones proteosuria, occurs with a condition of diffuse malignant 

 tumour (sarcoma) of the bone-marrow. 



Proteoses may be distinguished from albumin by the fact that the 

 precipitate with nitric or salicylsulphonic acid disappears on heating, 

 and reappears on cooling. The Bence-Jones proteose is further 

 characterized by the fact that urine containing it becomes opaque 

 at a comparatively low temperature (60 C.), with the formation of 

 a sticky coagulum. If the reaction be acid, this coagulum disappears 

 on further heating, and reappears on cooling. With strong hydro- 

 chloric acid this proteose gives a sharp ring, which also disappears 

 on heating and reappears on cooling. 



Blood. The red corpuscles or the blood-pigment may pass into 

 the urine. The former condition is known as k ' haematuria.'' the latter 

 as " haemoglobinuria.'' When the urine contains but little blood, 

 it presents a peculiar " smoky " appearance; with larger quantities, 

 the urine appears red or reddish -brown, according to the variety of 

 blood-pigment present. The presence of blood is detected clinically 

 by making some of the urine strongly alkaline with caustic soda, and 

 boiling. Should blood be present, a reddish-brown deposit is formed, 

 with greenish fluid above. Various drugs taken by the patient, such 

 as senna, rhubarb, may yield a similar result. The " guaiac test " 

 (see p. 112) also serves to identify blood. There are certain fallacies 

 in this test. Iodides in the urine may give it; also the presence 

 of saliva, through spitting into the pot, and pus. In hsematuria, 

 blood-corpuscles may be detected in the sediment after centrifuging 

 or allowing the urine to stand. The spectra of oxyhaemoglobiii or 

 methsemoglobin may be obtained ; more often the latter. 



Occasionally, alkaline haematoporphyrin is met with in considerable 

 quantities in the urine, giving it a dark, port-wine colour. This is 

 generally due to poisoning by drugs, such as sulphonal. Such a 

 urine will not give the guaiac test, owing to the absence of iron in 

 haematoporphyrin. To identify it, the pigment should be converted 

 into the acid variety by the addition of hydrochloric acid, and, if 



