710 CERTAIX ABXORMAL CONDITIONS OF THE URINE. 



information sufficiently definite to determine the causes of the 

 change of colour, nor the substances Avhich produce it, or their 

 modes of formation, there is yet evidence enough to satisf}' 

 us that the ultimate source of this colouring matter is the 

 blood ; and that probably the amount of the chief colouring- 

 principle met with — ursematine — is a not incorrect indication 

 of the amount of change which the blood-globules are under- 

 going. 



' We find that in some inflammatory actions, and in certain 

 febrile disorders, as also in special diseases of the liver, this 

 pigment is much increased. From exjieriments which have 

 been made by Klihne, it would seem that in the course of the 

 complicated relations which subsist between the liver and the 

 kidneys, there is in the disturbance of the functions of the 

 former a passing of bile acids or products into the blood ; that 

 these, acting upon changing blood-corpuscles, convert their 

 colouring matter into a special pigment which escapes by the 

 urine. While of blood-pigment itself, independent of and apart 

 from the blood-globules, we have no doubt that such maj^ be 

 found unchanged in the urine, having passed off from changed 

 blood-corpuscles with the water from the kidneys; or the 

 formed materials may themselves have passed through their 

 vessels, and ultimately undergone disintegration and separation 

 of their colouring matter in the renal tubes. 



These two latter conditions and causes of colouring of the 

 urine are quite distinct from colouring by either bile or blood- 

 corpuscles themselves. 



e. Alteration of the other Organic Coirfpounds, the Acid 

 Constituents and Extractive Matters. — Both the quantities of 

 the complex animal matters known as extractive, and the 

 special acid, free or combined, of the horse's urine — hippuric 

 — are in disturbed conditions of the system, and in special 

 organic changes, liable to be increased or diminished in amount. 

 Although it is probably quite true that hippuric acid is largely 

 indebted for its formation to the character of the food taken, it 

 seems yet doubtful whether it owes its entire existence to this 

 source, or is not largely manufactured in the liver from the 

 glycocol formed there. Chemical changes occurring amongst 

 the tissues and elements of the body have probably more in- 

 fluence in determining its production than variations of food. 



