BLOOD ANALYSIS 271 



It will be noted* that in chronic nephritis the principal change is in 

 the urea and non-protein nitrogen of the blood which may increase 

 considerably. In severe cases associated with uremia the retention of 

 these forms of nitrogen may be very great and there is a consequent 

 rise in the blood content which may amount to 1000 per cent or more. 

 In uremia there is likewise a great increase in other individual nitroge- 

 neous components of the blood such as uric acid, creatinine, creatine, 

 amino-acid nitrogen, and even of ammonia. The increase in creatinine 

 has been shown by Myers and Fine and others to be significant, inas- 

 much as this increase does not appear to occur in other types of nephritis. 

 Uric acid is greatly increased in uremia and may be very much higher 

 than in gout. Associated with uremia there is ordinarily an acidosis. 

 There may be an increase in the sugar of the blood and a very great 

 increase of the acetone bodies present. An increase is also generally 

 found in cholesterol and in the various forms of phosphorus of the blood. 



In diabetes the most noteworthy changes are in the content of glucose 

 and of acetone bodies. Glucose may be increased above the normal 

 (about o.i per cent) to 0.15-0.80 per cent. The increase in acetone, 

 diacetic acid and hydroxybutyric acid is very marked in comparison 

 with the minute amounts found in normal blood. There may also be 

 an increase in fat and other lipoids in severe diabetes. 



In gout the characteristic change is in the uric acid content which is 

 almost always considerably increased. Other forms of nitrogen are 

 affected but little. In arthritis the blood may also be high in uric acid 

 but in this case ordinarily there is a rise in non-protein nitrogen also. 



Lipemia is usually associated with an increased sugar content of the 

 blood. The fat content in this condition has been found as high as 29 

 per cent. There is a correspondingly large increase in the cholesterol 

 of the blood. 



In cholelithiasis there appears generally to be a fairly marked 

 increase in the cholesterol content of the blood and this determination 

 is thus of diagnostic aid. Some increase may also be found in other 

 disorders as in nephritis, severe diabetes, pregnancy, alteriosclerosis 

 and syphilis. 



METHODS 



Non-protein Nitrogen. (a) Colorimetric Method of Folin and Denis. 1 

 Principle. This method, which is simple and convenient, depends 

 upon the removal of the proteins from a sample of blood by precipita- 

 tion with methyl alcohol, and the estimation of nitrogen in the methyl 



1 Folin and Denis: /. BloL Chem., u, 527, 1912. 



