SANITARY STUDIES OF BAKING POWDERS 



6. Comment on the data in the preceding papers (2-5) on the 



best available method for the quantitative determination 



of aluminium in biological materials^ 



WILLIAM J. GIES 



(Biochemical Laboratory of Columbia University, at the College of Physicians 



and Surgeons, New York) 



(Received for publication, May 31, 1916) 



An examination of the data in the four preceding papers shows 

 that Howe, Curtman and Gross, and Smith and Hawk, agree in the 

 general conclusion that the Schmidt-Hoagland method is somewhat 

 more accurate and serviceable than the Steel method for the estima- 

 tion of aluminium in biological materials, and that the Steel method 

 gives low results. Steel finds that the Schmidt-Hoagland method 

 is more convenient but not more accurate than his own. 



Curtman and Gross attribute the observed losses, by the Steel 

 method, to the decomposition of ferric phosphate in the precipitated 

 mixture of aluminium and ferric phosphates (page 169). 



These findings suggest that possibly the results for aluminium, 

 in the earher experiments by SteeP and Kahn^ {with Steel' s 

 method), were low and that more aluminium was ahsorhed from 

 the aluminized hread, in those experiments, than the data reported 

 by Steel, and by Kahn, indicafed.'^ 



After the authors of the four preceding papers (2-5) had cor- 

 rected and returned to me the corresponding proofs, I forwarded to 

 each author a copy of the first paragraph above with a copy of the 



1(2) Howe: Biochemical Bulletin, 1916, v, p. 158 j (3) Curtman and 

 Gross: Ibid., p. 165; (4) Steel: Ibid., p. 173; (S) Smith and Hawk: Ibid., p. 183. 

 2 Steel: Amer. Jour. Physiol., 1911, xxviii, p. 94- 

 ' Kahn : Biochemical Bulletin, 191 i, i, p. 235. 

 4 Gies : Ibid., 1916, v, p. 152. 



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