BLOOD ANALYSIS 



295 



light reflected from the particles of the suspension. The brightness 

 of the two fields is compared instead of their colors. It is adapted 

 particularly for the determination of substances that in very dilute 

 solution may be precipitated in the form of suspensions which do not 

 agglutinate appreciably in the time required for making readings 

 (10-20 minutes). The method has been adapted to the determination 

 of proteins in digestion mixtures, milk, urine, etc.; 1 nucleic acids; 2 

 chlorides, 8 phosphates, and phosphatides in blood, etc.; 4 fats in milk, 

 blood, etc.; 5 acetone bodies in urine and blood; 6 uric acid and purine 

 bases; 7 ammonia; 8 calcium; 9 silver, etc., 

 and is continually finding new applica- 

 tions. It is possible to determine very 

 minute amounts of substances, entirely 

 outside of the range of gravimetric 

 methods of analysis, and hence the 

 procedure may be used where the 

 amount of material is very 'limited. If 

 properly carried out the limits of error 

 of the method are not greater than those 

 of the colorimetric methods commonly 

 used. Below will be found descriptions 

 of and figures representing two satisfac- 

 tory types of nephelometer. 



The Duboscq colorimeter has been 

 adapted for nephelometric purposes by 

 Kober 10 andbyBloor. u Bloor's nephelom- 

 eter is illustrated in Figs. 94 and 95. The FlG 94 ._ BLOOR , S NEPHELO METEK. 

 brass plate carrying the colorimeter 



plungers is replaced by the plate A with two slots in which are sup- 

 ported the nephelometer tubes B with their flanges resting on the edges 

 of the slots. The slots are so cut that the center lines of the tubes are 

 exactly in line with the centers of the lower openings of the prism 

 case E. If desired they may be countersunk to receive the flanges. 



1 Kober: Jour. Biol. Chem., 13, 485, 1913; Jour. Am. Ch. Soc., 35, 1585, 1913; Folin 

 and Denis: Jour. Biol. Chem., 18, 273, 1914. 



1 Kober and Graves: Jour. Am. Chem. Soc., 36, 1304, 1914. 



Richards: Zeitschr. f. anorg. Chem., 7, 269, 1895. 



4 Greenwald: Jour. Biol. Chem., 21, 29, 1915; Bloor: Jour. Biol. Chem., 22, 133, 1915; 

 Kober and Egerer: Jour. Am. Chem. Soc., 37, 2373, 1915. 



Bloor: Jour. Biol. Chem., 17, 377, 1914; /. Am. Chem. Soc., 36, 1300, 1914. 



'Folin and Denis: Jour. Biol. Chem., 18, 263, 1914; Marriott: same, 16, 289, 1913.. 



7 Graves and Kober: Jour. Am. Chem. Soc., 37, 2430, 1915. 



Graves: /. Am. Chem. Soc., 37, 1181, 1915 



'Lyman: Jour. Biol. Chem., 21, 551, 1915. 



10 Kober: Jour. Biol. Chem., 13, 485, 1913; Jour. Am. Chem. Soc., 35, 1585, 1913. 

 11 Bloor: Jour. Biol. Chem., 22, 145, 1915. 



