116 EXPEBIMEKT STATION EECOED. 



A study in drying urine for chemical analysis, W. W. Beam an (Jour. 

 Biol. Chem-., 19 {19U), No. 1, pp. 105-113).— In these investigations it was 

 found that some urines from herbivora on drying lose nitrogen from ammonium 

 compoimds and free ammonia, in some cases as much as 50 per cent of this 

 nitrogen. Tlie main loss of nitrogen, however, comes from the decomposition 

 of ammonium carbonate rather than from that of urea or hippuric acid. The 

 carbon loss, vs^iiich consists of carbon dioxid, is in excess of what would be 

 necessary to combine with the ammonia to form normal cai-bonates, and comes 

 partly from the bicarbonates. The total carbon and total hydrogen can be 

 determined directly by combustion in a quartz combustion tube using the ordi- 

 nary combustion furnace. 



The quantitative estimation of urea, and indirectly of allantoin, in urine 

 by means of urease, R. H. A. Plimmer and Ruth F. Skelton (Biochem. Jour., 

 8 (1914), No. 1, pp. 70-73). — "The estimation of urea in uriue is quiclvly and 

 accurately made by decomposing it with urease (1 gm, powdered soy bean) 

 at 35 to 40° C. for one hour. During this time the ammonia evolved is removed 

 by an air current, as in Foiin's method for estimating ammonia. One gm. of 

 anhydrous sodium carbonate is then added and the air current is continued 

 for another hour. Liquid paraffin is very convenient for lessening the frothing. 

 Since urease does not decompose allantoin, and since both allantoin and urea 

 are quantitatively decomposed by the magnesium chlorid method of Folin, the 

 amount of allantoin in those urines which contain both compounds is readily 

 estimated by difference." 



A permanent preparation of urease, and its use for rapid and accurate 

 determination of urea, D. D. Van Slyke and G. E. Cullen (Jour. Amer. Med. 

 Assoc, 62 {1914), No. 20, pp. 1558, 1559, fig. 1; Jour. Biol. Chem., W (1914), 

 No. 2, pp. 211-228, figs. 3). — Soy-bean meal is extracted with five parts of 

 water and the extract is poured into ten volumes of acetone. The precipitate 

 containing the enzym is dried and obtained as a powder, which is said to main- 

 tain its action indefinitely. The ammonia evolved is collected in fiftieth-normal 

 acid, which may be either hydrochloric or sulphuric. 



METEOROLOGY. 



Relation of climate to plant growth in Maryland, F. T. McLean (Mo. 

 Weather Rev., 43 (1915), No. 2, pp. 65-72, figs. 5).— Selected strains of wheat, 

 corn, soy beans, and Windsor beans were grown in nine different localities on 

 the same type of soil in 6-in. pots sunk in the ground, and an attempt was made 

 to correlate the growth of the plants with the meteorological environment, viz, 

 rainfall, evaporation, temperature, and sunshine. To eliminate the disturbing 

 influence of drought, the soil moisture in the pots was prevented from falling 

 below the optimum by the use of an autoirrigator. Evaporation was measured 

 by means of a Livingston atmometer. 



Only the results obtained with soy beans at Oakland and Easton are dis- 

 cussed, in this article. These indicate that with a sufficient supply of moisture 

 provided for, the soy bean " exhibited a pronounced and somewhat regular 

 march of its growth rate (as measured in terms of the dry-weight material 

 accumulated in leaves and stems during the first month of its growth from 

 seed) throughout the growing season," the maximum rate of production of dry 

 matter occurring in the warmest part of the season. " The growth rate tended 

 to vary almost directly with the 'temperature index' [mean daily temperature 

 above 40° F.] when the air temperatures were low. With high air temperatures 

 the growth rate was relatively much greater than can be accounted for by the 

 ' temperature indexes ' alone. The agreement in this regard between the data 



