1»191 AGBICULTURAL CHEMISTRY — AGROTECHNY. 617 



A comparison of the ammonia and urea content of muscle as determined by 

 this method with that of blood estimated by a new micro method indicates that, 

 contrary to the results of earlier investigators, the concentration of ammonia is 

 the same in muscle and In blood. If muscle is left for some time an Increase 

 in the concentration of ammonia takes place with a corresponding decrease 

 in urea, the sum of the two values remaining constant. The concentration of 

 ammonia in bile, spinal liquid, and aqueous humor is also reported to be the 

 same as in blood. 



The microdeterminatlon of nitrogen by direct nesslerization and of total 

 solids, in drop quantities of human blood, A. W. Peters {Jour. Biol. Chem., 

 SO (1919), No. 2, pp. 285-298).— A method is described for the determination of 

 total and nonprotein nitrogen and of total solids in 15- to 30-drop quantities of 

 human blood. 



If the three determinations are to be made on the same composite sample, a 

 maximum of 30 to 35 drops of blood is collected in a weighed centrifuge tube 

 containing a small amount of 0.5 per cent sodium fluorid solution. The tube is 

 rotated to mix the contents, weighed to determine by difference the weight of 

 blood, and made up to a volume of 8.5 cc. with the sodium fluorid solution. 

 One cc. of this volume is pipetted Into a graduated cylinder and diluted with 

 the collection medium to such a volume that the liquid will represent about 

 10 nig. of blood per centimeter. This is used for duplicate determinations of 

 total nitrogen. 



For the determination of total solids, 2 cc. of the original dilution of blood 

 is pipetted into a small tube containing a few decigrams of pure dry talcum 

 powder. The tube is rotated to distribute the powder uniformly over the inner 

 surface, and is then heated In a nearly horizontal position in a drying oven at 

 75° 0. to constant weight. For nonprotein nitrogen, two determinations are 

 made with 2 cc. each of the original dilution of blood or one of 5 cc, depending 

 upon whether about 30 or about 15 drops of blood have been collected. 



Standard conditions for conducting the KJeldahl digestion for both the total 

 and nonprotein nitrogen and for the direct nesslerization of the digests are 

 described in detail. The chief feature of the latter determination is the use of 

 an Inorganic color standard, which is matched In varying amounts against a 

 fixed length of column of the different unknowns, and not vice versa as Is 

 customary. The standard solution is made by dissolving 6 gm. of ferric am- 

 monium sulphate in 75 cc. of cold distilled water, adding 2 cc. of a 1 per cent 

 picric acid solution, and making the volume up to 100 cc. with distilled water. 

 The mixed color standard is said to remain perfectly clear and of constant 

 Intensity of color for a week or more. The quantitative evaluation of the 

 colorimetric results has been adjusted to variations of analytical conditions, 

 so that the variability and certainty of results are said to lie within a few 

 thousandths of a milligram of nitrogen. 



Determination of ammonia In blood, O. Folin (Jour. Biol. Chem., 38 (1919), 

 No. 2, pp. 259, 260). — The author calls attention to numerous sources of error 

 encountered In the determination of ammonia In blood by the method de- 

 scribed by Morgulis and Jahr (E. S. R., 41, p. 413). 



Bacon curing on the farm, J. B. Fisheb (Rhodesia Agr. Jour., 16 (1919), No. 

 S, pp. 202-209, pis. 4). — This article contains suggestions for the selection and 

 fattening of pigs to be used for bacon, a list of tools necessary for farm bacon 

 curing, directions for slaughtering, methods for curing the bacon by the dry 

 salt and brine processes, and a description of a simple snfokehouse. 



Home drying of fruits and vegetables in Washington, F. O. Kbeager and 

 I. N. Armstrong (Wash. State Col. Ext. Dept., Ser. 1, No. 58 (1919), pp. 31, figs. 

 7). — This bulletin deals with the principles of food preservation In general, the 



