344 HEALTH AND DISEASE 



microscopical examination, which reveals the existence of small biconcave 

 discs or red blood corpuscles (fig. 140). (See "Blood".) 



Haemoglobin (fig. 141), the substance contained in the red cells of 

 the blood, is found in the urine in that sudden and fatal disease known 

 as Hemoglobinuria, and imparts to it the colour of porter. AVhen allowed 

 to stand, the urine in this disease throws down a blackish-brown granular 

 flocculent deposit. 



If a few drops of nitric acid be added to a small quantity of the 

 fluid, a dense precipitate of coagulated albumen will be formed, and the 

 same result will follow if the urine be heated in a test-tube over the 

 flame of a spirit-lamp. 



Pus (matter) is sometimes found in the urine, and when existing in 

 considerable amount imparts to it an opaque, milky-looking appearance. 



Fig. 141. — Hemoglobin Crystals from the Blooi 



Fig. 142.— Pus 



A, Pus cells. B, Pus cells treated with acetic 

 cid, showing nuclei. c, Pus cells " budding". 



If a small quantity of the urine be set aside in a glass, and allowed to 

 stand, the pus settles down to the bottom as a creamy-looking sediment. 

 When such a deposit is examined with a microscope it is found to consist 

 of small, pale, nucleated or granular-looking cells (fig. 142). 



A few pus corpuscles may be frequently found in the urine of old horses 

 and mares, which in other respects exhibit no signs of disease. They are 

 mostly the result of a slight irritability of the bladder or prostate, uterus 

 or vagina. 



When pus exists in quantities sufficient to impart an opaque appear- 

 ance to the urine, it may be presumed that there exists some active disease 

 in some part of the mucous membrane of the genito-urinary organs, or 

 in the prostate gland, or the kidney. It is mostly derived from the 

 bladder, as the result of irritation excited by a calculus, or from a chronic 

 catarrhal state of the mucous membrane. In abscess of the kidney a large 

 amount of pus is found in the urine. 



