1912] 'Alfred P. Lothrop 185 



frort! the boat. Specimens of the same catch were immediately 

 placed in storage and delivered to us, at intervals, in a frozen State, 

 when they were thawed under uniform conditions and promptly 

 subjected to analysis. 



Comparative data were obtained regarding moisture, organic 

 matter, inorganic matter, and total solids; ammonia nitrogen, solu- 

 ble nitrogen, insoluble nitrogen, coagulable nitrogen, non-coagulable 

 nitrogen and total nitrogen; "proteose" nitrogen, both before and 

 af ter autolysis ; f at content and f atty-acid number ; and the reducing 

 power of the aqueous protein- free extract, as determined by the 

 Benedict method. 



The flesh of fish which had been refrigerated not less than four 

 months and not more than six months was unaltered in composition. 

 After a period of nine months in cold storage there was a sHght, 

 almost imperceptihle, increase in the content of ammonia nitrogen, 

 but no other change was noted. The work is in progress. 



41. An attempt to sharpen the end point in Benedict's 

 method for the quantitative determination of sugar in urine. 

 William Weinberger. In Benedict's modification of FehHng's 

 sugar titration method "instead of the reduced copper being pre- 

 cipitated as the red sub-oxid, which of its own color obscures the 

 end point of the reaction, the copper is precipitated as cuprous sulfo- 

 cyanate, a snow white Compound, which is rather an aid than a hin- 

 drance to accurate Observation of the disappearance of the last trace 

 of blue color," However, in applying Benedict's method to urine 

 of low sugar content (below 0.5 per cent., as it frequently occurs in 

 cases of glycosuria), one is Struck by the fact that the blue color of 

 the mixture does not persist until the reaction is ended, for the 

 Contents of the porcelain dish assume a dirty brownish-green hue 

 that gradually merges into brown. This renders the correct estima- 

 tion of the end point very difficult if not impossible. 



Clarifying the urine by the addition of lead acetate previous to 

 the titration might overcome the difficulty, but this procedure would 

 require additional manipulations and calculations ; and there is also 

 the danger of a chemical change in the copper Solution. None of 

 these objections apply to the simple method proposed by the author. 

 It consists in the addition, just before heating, of approximately 10 



