66 Cold-Storage of Fish [Oct. 



creased solubility of nitrogeneous substances. In the case of 

 chicken, Hoiighton reports a slight increase in "soluble nitrogen" 

 for light meat and a slight decrease for dark meat. 



" Coagulable nitrogen " and " non-coagulable nitrogen." 

 From the data in the tables it appears that there was a very slight 

 increase in " coagulable nitrogen " and a corresponding decrease in 

 "non-coagulable nitrogen." These dififerences are too slight to 

 Warrant any inferences. 



Lipins. The term lipins is used to indicate the fats and fat-like 

 substances in the "ethereal extract."^^ The flesh of the winter 

 flounders that were used for the determinations was comparatively 

 poor in ether-soluble constituents. The actual weight of lipins neu- 

 tralized at any time was always less than one gram. This admits 

 of relatively large degrees of experimental error; according to 

 Allen, ^^ 5 to 50 gm. of material should be used for this determina- 

 tion. Other authors recommend at least 4-5 gm. In our work such 

 large samples were not available. While the values here reported 

 are possibly somewhat too high, it is significant that there is no 

 increase in acidity during a nine months' period of storage. 



It is difficult to believe that the lipins would undergoany changes, 

 significant of deterioration in nutritive value, which would not be 

 shown more strikingly by the protein constituents of the flesh. The 

 negative findings in this particular connection accord with such a 

 view of the matter. 



Reducing substances. We determined the reducing power of 

 aqueous extracts, in order to detect any sugar which might have 

 resulted from the hydrolysis of glycogen during the cold-storage 

 period. A similar determination was made by Williams,^*^ but her 

 method involved the hydrolysis of all carbohydrate-yielding sub- 

 stances. She treated fish-powder with boiling dilute hydrochloric 

 acid Solution under a reflux condenser for three hours; proteins 

 were removed by precipitation with lead acetate ; then, after removal 

 of the excess of lead, the reducing power of the filtrate was de- 

 termined by the Fehling method and reported as percent. of glucose. 



18 Rosenbloom and Gies: Biochemical Bulletin, 1911, i, p. 51. 

 18 Allen : Com. Organic Anal. (3 ed.). Vol. 2, pt. i, p. 105. 

 20 Williams: Trans. Chem. Soc, 1897, Ixxi, p. 651. 



