CONSTANCY IN THE LEVEL OF BLOOD LIPIDS 391 



Although variations in analytical technic and in other experimental con- 

 ditions render it difficult to draw any far-reaching conclusions from values 

 obtained by different workers, it is probably worth while to list the values 

 for some blood constituents as reported in the literature. 



a. Total Lipids. The values for total lipids (total fatty acids plus 

 cholesterol) in the whole blood of dogs (expressed as milligrams per 100 ml. 

 moist weight), as reported by Terroine, 208 were as follows: sixteen dogs, Av. 

 454 (314-669); six dogs, Av. 429 (353-495); and seven dogs, Av. 442 

 (314-564). The Kumagawa-Suto method was used for the estimation of 

 fatty acids, and the Windaus digitonin procedure for cholesterol. Using 

 similar procedures, Lattes 221 reported the mean value for total lipids in the 

 venous blood of thirteen dogs as 382 milligram per cent ; the range was from 

 303 to 428 milligram per cent. 



The values for the content of total lipids in dog blood as reported by 

 Bloor are considerably higher than those reported above. This is to be 

 ascribed to the fact that the latter investigator used a nephelometric method 

 for total lipids and fatty acids which yields a considerably higher result than 

 does the Kumagawa-Suto procedure. Moreover, a colorimetric technic 

 was employed for the estimation of cholesterol, which likewise gives a higher 

 value than does the digitonin precipitation method. The results of Bloor 

 (expressed in milligram per cent for whole blood) are as follows : nine dogs, 

 Av. 590 (510-660) 222 ; five dogs, Av. 726 (600-850) 223 ; and seven dogs, 

 Av. 820 (700-980). 224 When the estimations were made on the blood 

 plasma, the results were as follows: seven tests on two dogs, Av. 840 (690- 

 1130) 7 ' 224 ; and six dogs, Av. 470 (380-620). 7 - 225 In a series of normal dogs 

 in whose case an extraction procedure resembling the Kumagawa-Suto 

 method was employed, average total lipids were 342 milligram per cent 

 (15 analyses) with a range of 215 to 442 milligram per cent. 



Bloor 7 concludes that it is not possible to present satisfactory lipid stand- 

 ards for the blood plasma of dogs. A value of 400 milligram per cent is the 

 usual figure, but determinations showing levels of 300 to 600 milligram per 

 cent may still represent a normal lipid picture. 



b. Phospholipids. The averages reported by Bloor and associates for 

 phospholipids are extremely uniform in different series of tests, but here 

 again the individual determinations have a wide range. However, greater 



221 L. Lattes, Arch, expll. Pathol. Pharmakol. (Naunyn-Schmiedeberg's), 66, 132-142 

 (1911). 



222 W. R. Bloor, J. Biol. Chem., 19, 1-24 (1914). 



223 W. R. Bloor, J. Biol. Chem., 23, 317-326 (1915). 



224 W. R. Bloor, J. Biol. Chem., 24, 447-460 (1916). 



226 W. R. Bloor, E. M. Gillette, and M. S. James, J. Biol. Chem., 75, 61-83 (1927). 



