990 THE COMPLETE GRAZIER. BOOK x 



The researches of Frankland, Stohman, and Riibner have shown that 

 fat is not exactly two and a half times the value of starch, nor are starch, 

 the sugars, and cellulose of precisely the same value. The most 

 recent results show the relative values of equal weights to be about 

 the same as follows : 



Fat 2-29 



Starch I'OO 



Cane sugar and gum '97 



Grape sugar and milk sugar "90 



Cellulose (about) '86 



" We shall thus obtain the albuminoid ratio more accurately if 

 we reduce the various non-albuminoid constituents to their value 

 in starch by multiplying each by the respective factors just 

 quoted. 



" A far more serious source of error arises from the fact that in many 

 of the ordinary analyses of foods the nitrogen of the amides and of the 

 nitrates present is reckoned as if it existed as albuminoids ; the analyst, 

 in fact, has not determined the albuminoids present, but he has de- 

 termined the amount of nitrogen, and then reckoned that the whole of 

 this nitrogen was present as albuminoids. It is clear, then, that when 

 amides or nitrates are present in the food analysed, the amount of 

 albuminoids shown in the analysis is always in excess of the truth. 

 When the Germans employ this imperfect method of analysis they 

 term the result arrived at ' Rohprotein,' that is ' crude protein,' but 

 English analysts are unfortunately not in the habit of giving this 

 warning. It would be better if the calculated result from the total 

 nitrogen present was always designated as ' nitrogenous substance,' 

 and not as ' albuminoids.' The present state of matters is a survival 

 of an old practice. Formerly no method was known for determining the 

 true albuminoids in a food, nor were chemists aware that amides were 

 always present in certain descriptions of food. Now analysts have 

 good methods for determining the true albuminoids present, but as yet 

 they generally adhere to the old and easy method of determining the 

 total nitrogen, and then multiplying its quantity by six- and- a- quarter. 

 It is certainly surprising that with good methods in their hands so 

 little has been done by chemists to determine the amount of true 

 albuminoids in various foods, and that so little use has hitherto been 

 made of the facts which have been ascertained. It must always be 

 borne in mind that the German ratios are still based on the quantities 

 of total nitrogen ; they are therefore in many cases not ' albuminoid 

 ratios,' but simply the ratios of nitrogenous to non-nitrogenous 

 matter. 



" The error we have pointed out occurs, however, only with certain 

 classes of food. Ripe seeds of all kinds contain only a small proportion 

 of amides, unless germination has commenced. Ripe straw contains 

 also but little amide. On the other hand, all green fodder crops, roots 

 and tubers, contain a considerable amount of amides, and nitrates also 

 may be present. In young grass 25 per cent, of the nitrogen usually 



