O. Folin and W. 8. McEllroy 519 
Sugar urines frequently contain albumin. Albumin does not 
destroy the accuracy of the sugar titration described in this 
paper. Because of the foaming produced by albumin it is, how- 
ever, desirable, indeed necessary, to use rather large test-tubes 
and to boil cautiously so that the contents do not boil over. The 
albumin does alter the appearance and probably also the com- 
position of the cuprous precipitate, making it more flocculent and 
bulky; but, as already stated, the end-point of the titration is not 
changed or obscured by the presence of albumin. 
THE JOURNAL OF BIOLOGICAL CHEMISTRY, VOL. XXXIII, NO.3 
