26 BLOOD AND ALBUMEN IN UKINE. 



actual state of the chemical pathology of the urine of animals 

 is so deficient, that we feel unable to do so. We can only 

 describe the method of 'ascertaining the presence of certain 

 substances, which sometimes undoubtedly occur in the urine 

 of animals, as they do in that of man. 



Blood is sometimes present in the urine. It may be 

 derived from the kidneys, ureters, bladder, or urethra. 

 When from the first of these sources, it gives a generally red 

 or smoky hue to the whole of the urine. When from the 

 urethra, the blood is generally expelled after the urine, often 

 dropping from the penis after the urine has ceased to flow. 

 Urine containing blood, from its containing albumen, coagu- 

 lates that is to say, becomes thick, and contains a sediment 

 when boiled. The sediment is not dissolved, that is to say, 

 the urine does not become clear on the addition of a few 

 drops of nitric acid. If a drop of the urine which is sup- 

 posed to contain blood be examined with the microscope, 

 the cells of the blood will be seen floating in it. This is the 

 only sure and reliable test of the presence of small quantities 

 of blood in the, urine. 



Albumen, as I have previously shown, is one of the most 

 important constituents of the liquor sanguinis of the blood. 

 In certain acute and chronic inflammations, and other dis- 

 eases of the kidneys, it finds its way into the urine; and there- 

 fore its presence in large amount is always of great importance. 



Albumen is recognised by its property of coagulating, 

 when a liquid containing it is boiled. The coagulum, or 

 precipitate, is not dissolved on the addition of nitric acid. 

 Nitric acid causes a precipitate, which is, in its turn, not dis- 

 solved by heat. When testing for albumen, if the urine be 

 alkaline, we should add a few drops of nitric acid before 

 boiling the fluid, for the alkali holds the albumen in solu- 

 tion. The two tests are quite sufficient to render us certain 



