BLOOD ANALYSIS 



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chlorides, 1 phosphates, and phosphatides in blood, etc.; 2 fats in milk, 

 blood, etc.; 3 acetone bodies in urine and blood; 4 uric acid and purine 

 bases; 5 ammonia; 6 calcium; 7 silver, etc., and is continually finding 

 new applications. 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 8 and by Bloor. 9 Bloor 's nephelom- 

 eter is illustrated in Figs. 83 and 84. The 

 brass plate carrying the colorimeter 

 plungers is replaced by the plate A with 

 two slots in which are supported 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 re- FlG . 8 ._ 

 ceive the flanges. The colorimeter cups 

 are replaced by the jackets C which project through the holes in the 

 cup supports F and are supported on them by the collars D. They 

 move when the cup supports move. The mirror is turned to the 

 horizontal position so that it reflects no light. The light in the nephe- 

 lometer comes from in front and not from below (see Fig. 84). The 

 nephelometer tubes are small test-tubes- 100X15 mm., preferably 

 made from the same sample of colorless glass tubing so that they are 

 of exactly the same bore. The flanges at the top should be well made 

 so that the tubes rest firmly and evenly in the slots. The glass should 



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



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

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



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



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



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



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

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



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



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



