154 



Scientific Proceedings (67). 



estimation of many of the substances occurring in minute amounts 

 in the body is a comparatively simple matter. 



In the hope of getting useful information, we have studied 

 quantitatively the proteins of cerebrospinal fluids with nephelo- 

 metric methods, and have correlated our findings with the Wasser- 

 mann reaction and other tests. 



Technic. 



The spinal fluid was accurately measured in a small graduated 

 cylinder or centrifuge tube, and an equal volume of .2 per cent, 

 tricresol added as a preservative. 1 This preserved the fluids for a 

 week or longer. 



For the total-protein estimation 2 c.c. of diluted fluid (corre- 

 sponding to 1 c.c. of original) were diluted with 8 c.c. of distilled 

 water, and then precipitated with 20 c.c. of 3 per cent, sulpho- 

 salicylic acid. If the amounts of fluid were small, one half or 

 one third these amounts were used. 



This suspension was then matched in the nephelometer 2 with 

 a standard made by adding 20 c.c. of 3 per cent, sulphosalicylic 

 acid to 10 c.c. of a .01 per cent, solution of casein. The readings 

 gave at once, upon calculation, the milligrams of total protein in 

 I c.c. of spinal fluid. If the standard was much stronger than the 

 "unknowns" a weaker casein solution was used, e. g., .005 per cent., 

 .0025 per cent., .00125 P er cent. 



For the total globulin estimation 2 c.c. of diluted fluid (1 c.c. of 

 original) were diluted with 3 c.c. .lN acetic acid and 5 c.c. of 

 saturated ammonium sulphate solution. This was also matched 

 to a casein standard as in the total-protein estimation. Theoret- 

 ically the standard should be of the same substance as the one to 

 be determined, yet here it seemed best to refer all the estimations 

 to an arbitrary standard for the sake of uniformity, speed and 

 convenience, as pure samples of these proteins are very difficult 

 to obtain. 



The euglobulin content in spinal fluid has been determined 

 heretofore by one third saturation of ammonium sulphate, but 



1 S. S. Graves and P. A. Kober, Journal of Amer. Chem. Soc, XXXVI, 751 (1914). 

 s Kober, Journal of Biolog. Chem., 13, 485 (1913); Journal of Amer. Chem. Soc, 

 35, 290 (1913); ibid., 1585. 



