188 CLINICAL DIAGNOSTICS. 



converts the hemoglobin into hematin, it is precipitated with the 

 earthy salts and gives them a reddish brown color. 



The difference between oxyhemoglobin and methemoglobin 

 must be determined with the spectroscope. Oxyhemoglobin gives 

 two absorption bands between D and E, methemoglobin gives 

 one between C and D. 



The presence of hemoglobin may be due to admixture 

 of blood as such {hematuria) or to hemoglobin alone (hemo- 

 globinuria) . 



Hematuria is recognized by microscopic examination 

 of the sediment and the detection of blood corpuscles. The 

 admixture of blood can occur in the kidney, the pelvis of 

 the kidney, the bladder or the urethra. It occurs most fre- 

 quently in red water, acute nephritis, renal calculi, hemor- 

 rhagic infarction of the kidney, pyelonephritis, acute cystitis, 

 cystic calculi. 



Hemoglobinuria consists in the presence of hemoglobin 

 (without the blood corpuscles) in the urine. The coloring 

 matter is derived either from the blood or the muscles. Ac- 

 cordingly we distinguish : 



a. Hematogenic or toxemic hemoglobinuria in red- 

 water of cattle and in Texas fever, also in bad cases of pois- 

 oning which cause decomposition of the red corpuscles, in 

 extensive burns and in the course of severe infectious dis- 

 eases. 



b. Myogenic or rheumatic hemoglobinuria in azoturia. 



c. Indican — indoxyl sulphate of potash C s H N K 

 S 4 , occurs in all urine in moderate amount. It is de- 

 rived from the indol C S H-X formed in the alimentary canal 

 during putrefaction of albumin ; indol is oxydized into in- 

 doxyl C 8 H 6 N O H and then combines with sulphate of 

 potash to form indoxyl sulphate of potash — indican. The 

 urine of the horse contains on an average, 184 mg. per liter. 



If rapid putrefaction of albuminous substances takes 

 place in the alimentary canal the amount of indican is in- 



