RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



The origin and distribution of urea in nature. — Application of new methods 

 for the determination of urea based on the use of xanthydrol, R. Fosse {Ann. 

 Inst. Pasteur, SO {1916), Nos. 10, pp. 525-592, figs. 13; 11, pp. 642-676, fig. 1; 

 12, pp. 739-755). — The material reported is divided into a brief introduction 

 and five parts, as follows : 



I. The qualitative and quantitative gravimetric analysis of urea by means 

 of xanthydrol (pp. 531-592). — The reactions and the procedures are described 

 and discussed in detail. 



II. Proteins and urea (pp. 642-660). — Experimental data on the production 

 of urea by the'action of potassium permanganate and alkalis on various proteins 

 are submitted and the theory of the reactions diocussed. 



III. Synthesis of urea by oxidation of ammonia and carbohydrates or 

 glycerin. — The probable participation of carbohydrates and fats in the phe- 

 nomenon of ureogenesis (pp. 660-672). — ^Data submitted show that urea Is 

 abundantly formed when glucose, levulose, sucrose, dextrin, inulia, or even 

 cellulose is oxidized in the presence of ammonia. Glycerin and formaldehyde 

 gave similar urea production. 



IV. Demonstration of the presence of urea in the invertebrates (pp. 673- 

 676). — Urea was identified by the xanthydrol method in coeleuterates, echi- 

 noderms, worms, crustaceans, insects, and mollusks. 



V. Urea in plants (pp. 739-755). — The presence Oj" urea was demonstrated 

 in many of the common vegetables and food plants, such as spinach, carrots, 

 turnips, potatoes, cauliflower, melons, and pumpkins. It is indicated that the 

 property to synthesize urea is possessed not alone by higher plants, but also 

 by molds. Urea was also found in germinating grains and in inactive seeds. 

 During germination an accumulation of urea was observed in the embi'yo. 

 while it occurred in only very small amounts or was practically absent in the 

 cotyledons. Since the presence of urea has been demonstrated in plants, it is 

 indicated that both urea and urease must be present in the material simul- 

 taneously. The function of the urease is deemed tv be that of transforming 

 into ammonia and rendering assimilable the urea contained in the plant. 



Comparative analyses of fibrin from different animals, R. A. Goetneb and 

 A. J. WUERTZ {Jour. Amer. Chem. Soc, 39 {1917), No. 10, pp. 2239-2242) .—The 

 authors, at the Minnesota Experiment Station, prepared fibrin from the blood 

 of cattle (two samples), sheep, and swine, and determined the nitrogen dis- 

 tribution by the Van Slyke method (E. S. R., 26, p. 22). 



The analytical results obtained showed no differences between the various 

 samples significantly greater than the usual experimental errors. From the 

 results it appears that " fibrin from any of these sources can be used inter- 

 changeably in experimental work without invalidating the results. Whether or 

 not this is true for fibrins from other sources remains still an open question." 



The data are repo-ted in tabular form. 

 110 



