14 EXPEHIMENT STATION RECORD. [Vol. 41 



once with 2 per cent acetic acid and twice with water, adding 5 gm. of fine 

 jacli bean meal and 100 cc. of 30 per cent alcohol, shaking gently but con- 

 tinuously for ten minutes, and filtering. The filtrate, which is said to contain 

 practically the whole of the urease and but little other material, is used in 

 amounts of 1 cc. for 1 cc. of diluted urine (1:10) and the digestion and 

 nesslerization conducted as usual, employing the Nessler reagent described in 

 the article noted above. 



A rapid method for the estimation of urea in urine, J. B. Sumner and A. 

 BoDANSKY (Jour. Biol. Chem., 38 {1919), No. 1, pp. 57-6i).— The method, which 

 is said to be rapid, accurate, and simple, consists essentially in treating a small 

 quantity of urine in a centrifuge tube with an approximately neutral phos- 

 phate solution and with urease. After the urea has been decomposed a pro- 

 tein precipitant (acidified potassiomercuric iodid solution) is added, the tube 

 centrifuged, and an aliquot of the clear supernatant liquid nesslerized and 

 compared wth a standard. The preparation of reagents and method of proce- 

 dure are described in detail. 



The proximate analysis of wood, W. H. Dore [Jour. Indus, and Engin. 

 Chem., 11 (1919), No. 6, pp. 556-563) .—This preliminary report of a study con- 

 ducted at the California Experiment Station on the chemistry of certain 

 California woods from the standpoint of their chemical utilization, deals with 

 the analytical methods employed and results obtained in a complete proximate 

 analysis of these woods. The analyses included determination of loss on dry- 

 ing, extractives soluble in benzene, extractives soluble in alcohol, substances 

 soluble in water, substances soluble in 1 per cent sodium hydroxid solution, 

 cellulose, and lignin. The woods studied were redwood, yellow pine, live oak, 

 and blue gum. 



Sawdust was found to be the most satisfactory mechanical condition of wood 

 for analytical purposes. Cellulose was determined by a modification of the 

 Cross and Bevan method involving chlorination in vacuo, and lignin by Konig's 

 method with 72 per cent sulphuric acid. 



In the analysis of coniferous woods by these methods 96 to 97 per cent of 

 the wood constituents were accounted for, while in the case of the hardwood 

 examined the lignin determinations failed and only from 83 to 91 per cent of 

 the wood constituents were obtained. 



Nitrating of woodpulp cellulose, S. D. Wells and V. P. Edwardes (Paper, 

 23 (1919), No. 23, pp. 180-185, fig. 1). — The authors report an investigation 

 conducted at the Forest Products laboratory, U. S. Department of Agriculture, 

 on the utilization of woodpulp as a source of nitrocellulose. The determination 

 of yields from laboi'atory nitrations indicated that under favorable conditions a 

 yield of 150 per cent nitrocellulose would be obtained from woodpulp, with a 

 corresponding yield of from 160 to 165 per cent from cotton. The pyro grains 

 from both soda and sulphate pulps prepared from jack pine were dark brown, 

 but the nitrocellulose from unbleached sulphite was as light colored as that from 

 cotton, having lost the yellow coloration from nitration in the boiling and 

 poaching treatments. The products from all the pulps studied met the labora- 

 tory tests for completeness of washing, stability, and purity of product. 



The factory runs on the woodpulps seem to indicate the suitability of wood- 

 pulp properly manufactured for the production of nitrocellulose. 



Studies on canning. — An apparatus for measuring' the rate of heat pene- 

 tration, W. T. BoviE and J. Bronfenbrenner (Jour. Indus, and Engin. Chem., 

 11 (1919), No. 6, pp. 568-570, figs. 5). — The apparatHS described was devised to 

 find the rate of transfer of heat from the outside toward the center of cans of 

 food during the process of cooking and sterilization, as affected by the variations 



