RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



The calculation of the protein from the nitrogen content of the 

 seeds of plants, H. Rittiiauskn {Landic. Vers. Stat., 47 {1896), JSfo. 

 4 and 5, pp. SOl-iOO). — Tlie author calls attention to the inaccuracy 

 of tlie factor 6.25 for calculating* protein in foods and feeding stuffs. 

 This factor is based on a nitrogen content for the proteid constituents 

 of 10 i^er cent, which he believes is not in accordance with our present 

 knowledge of the comi^osition of these bodies. In evidence of this he 

 gives a compilation of the elementary analyses of the i)roteid bodies 

 separated from various cereals, leguminous and oil-bearing seeds, and 

 oil cakes. Omitting some of the oil-bearing seeds of little agricultural 

 importance, the nitrogen content of the proteids is given in the table 

 on the following page. 



With reference to this table the author says: ''It is apparent 

 that in most cases the proteid bodies of plant seeds contain nuich more 

 than 1(3 per cent of nitrogen. Those of the cereals and most legumes 

 grown here average about 17.C j^er cent, and of the oil-bearing seeds 

 about 18.2 per cent. This gives the factor 5.7 for calculating the pro- 

 tein of cereals and leguminous seeds, and 5.5 for that of oil-bearing 

 seeds (and cakes) and lupines. The only exceptions to the rule are 

 barley, corn, buckwheat, soja beans, and white beans, the average for 

 which is 10.06 per cent, giving the factor 0; and among the oil-bearing 

 seeds, rape and candle nuts (Aleurites triloba), for which is likewise 

 the best factor." 



The protein is calculated from the average nitrogen content of the 

 seeds, using the factor 6.25, and in comparison the suggested factors 

 5.5, 5.7, and 6, respectively. This shows that the factor 6.25 gives a 

 much larger percentage of protein than is believed to be actually 

 present, and in the case of many oil cakes this is 1 or 5 i^er cent too 

 high. 



A number of experiments are given in determining the protein 

 directly, which indicate that there could not be as much present as 

 calculated by the factor 6.25. The adoption of a more correct factor is 

 urged. 



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