124 



as j.(>latiiu)ids. After doductiiio- the fat and insoluble ash, the residue 

 loft after tn^atnient with hot water was designated '' insoluble proteid" 

 (FU'isfhfaser). 



Atwater and his associates, in their study of the chemical composi- 

 tion of lish flesh, determined the inoredients soluble in cold and in 

 hot water in a numl^er of samples. I'hey prepared the extract by 

 digesting 33.33 grams of the freshly chopped flesh eighteen to twenty- 

 four hours in 'yOi) cubic centimeters of cold water and then filtered it. 

 Tlie sohil)lc albumin was determined by heating the cold-water extract 

 to coagulation, filtering, washing with water and ether, drying, and 

 weighing. The total amount of matter other than coagulable proteid 

 dissolved l)y the cold water was determined ])y evaporating to dryness 

 measured quantities of the filtrate from the coagulable proteid and 

 weighing. One sample of the dry residue was used for the determi- 

 nation of the ash, and another finely ground Avas used for the estima- 

 tion of fat. The total quantity of ash and fat thus obtained was 

 subtracted from the crude extract in order to get the true extract, 

 which was designated "extractive matters." The same investigators 

 also determined the gelatinoids in fish flesh by treating the residue, 

 insohible in cold water, with boiling water for about twenty hours. 

 The resulting solution was then filtered, the filtrate evaporated to 

 dryness, and weighed as crude gelatin. In this fat and ash were 

 determined and the pun^ gelatin was estimated l)y deducting the quan- 

 tities of ash and fat from the crude residue left upon evaporation. 

 The methods used by Atwater and coworkers are quite similar to those 

 used by Almen, but it is apparent from the records available that in 

 the American work greater precautions were taken with certain 

 determinations to get concordant and accurate results. 



Henneberg, Kern, and Wattenberg, in their investigation of the 

 chemical composition of mutton, determined the extractives by the fol- 

 lowing method: Fifty grams of the fresh flesh were repeatedly treated 

 with small quantities of cold water until the volume of the resulting 

 filtrates measured 1,000 cubic centimeters. Portions of this filtrate 

 were used for the estimation of ash, total dissolved matter, total nitro- 

 gen, and nitrogen in the solution after removing the coagulated albu- 

 min. The proteid nitrogen— i. e., that coagulated hy heat— was also 

 determined by difference. For purposes of comparison or as a test of 

 the accuracy of the work, the proteid coagulated by heat was also 

 removed, dried, and weighed. The figures for nonprotiud nitrogen 

 were multiplied by the factor 6.25 in order to get the amount of the 

 so-called nonproteid extractives. The results obtained by Henneberg 

 and associates with mutton flesh are comparal)h' wifh those of Atwater 

 and Almen with fish flesh. 



Stated briefly, the methods used by Wiley and associates were as 



