1M&] AGRICULTURAL CHEMISTRY — AGEOTECHNT. 207 



A simple method of determining uric acid and tyrosin in the same sample, 

 E. Herzfeld and R. Klingeb (Biochem. Ztschr., 88 (1918), Xo. J,, pp. 283-285). — 

 The method described makes use of the phenol reagent of Folin and Denis 

 (E. S. R., 28, p. 805), a saturated solution of sodium carbonate, and a standard 

 solution of either uric acid or tyrosin prepared as follows: One-tentb gm. of 

 the substance (tyrosin or uric acid) and 0.1 gin. of lithium carbonate are dis- 

 solved in 100 cc. of water at room temperature. One cc. of this solution is 

 shaken with 10 cc. of the phenol reagent for about five minutes, 30 cc. of the 

 saturated solution of sodium carbonate is added, and the whole made up with 

 water to 100 cc. The blue color which develops within 24 hours remains un- 

 changed for a longer time and is deeper in the case of tyrosin than of uric 

 acid. The tyrosin standard can be used in the determination of uric acid 

 by multiplying the figure obtained by the factor 0.68 and the uric acid standard 

 for tyrosin determination by the use of the factor 1.45. The technique of the 

 method is as follows: 



If the solution to lie tested contains protein and sugar, these must be re- 

 moved, the former by heat coagulation and the latter by fermentation with 

 yeast. One cc. of the protein sugar-free solution is then mixed with 10 •cc. of 

 the phenol reagent, shaken for about five minutes, and treated with sodium 

 carbonate solution exactly as the standards. After standing overnight, the 

 color matched against the tyrosin standard indicates the amount of uric 

 acid and tyrosin. One cc. of a fresh sample of the solution is then heated for 

 a few minutes with 0.5 cc. of 33 per cent sodium hydroxid solution and 3 drops 

 of a 3 per cent hydrogen peroxid solution to destroy the uric acid. After 

 cooling and adding 1 cc. of glacial acetic acid, the determination is repeitad 

 and the solution matched against the tyrosin standard. The difference be- 

 tween the figures obtained in the first and second determinations, calculated by 

 means of factors noted above, gives the amount of uric acid. 



The construction and use of a simple apparatus for the determination of 

 urea in blood, C. N. Peltrtsot ( Jour. Pharrn. et Chun.. 7. so:, 18 (1918), No. 3, 

 pp. 73-SO). — The apparatus consists of a small bottle in which is tightly fitted 

 a glass tube 9 cm. by S mm., the latter graduated to tenths of a cubic centimeter. 

 Into the apparatus are successively introduced by means of pipettes 5 cc. of 

 sodium hypobromite solution, 5 cc. of a 33 per cent sodium hydroxid solution, 

 12 to 15 cc. of water, and finally 10 cc. of defecated serum prepared by mixing 

 equal volumes of serum and 20 per cent trichloracetic acid, shaking and filter- 

 ing. The meniscus in the tube is read, after which the apparatus is inverted 

 with the opening closed by the finger. After the contents are thoroughly mixed, 

 the inverted apparatus is immersed in water in a vessel about 20 cm. deep, the 

 orifice is opened, and the inner and outer surfaces of the liquids arc adjusted 

 to the same level. After closing the orifice again, the apparatus is removed 

 and inverted and the position of the meniscus again read. The difference indi- 

 cates the volume of nitrogen produced. 



A method for the determination of fat in dried feces and its distribution 

 as soap, free fatty acids, and neutral fat, L. E. Holt, Anof.ua M. Courtney. 

 and Helen L. Fales {Amer. Jour. Diseases Children, 77 (1919), No. 1, pp. 88- 

 42, fig. 1). — The method described is an application to feces of the Rose-Gottlieb 

 method for determining fat in dried and condensed milk. The use of am- 

 monia to facilitate the separation of the fat from the protein is omitted on 

 account of the presence of the free fatty acids which would be saponified by the 

 ammonia. 



The method is considered to be superior to the Soxhlet extraction method in 

 that the technique is more simple, the amount of ether required for each deter- 



