414 EXPERIMENT STATION RECORD. [Vol.41 



A revised colorimetric method for determination of uric acid in urine, O. 

 FoLiN and H. Wu (Jour. Biol. Chem., 38 (1919), No. 3, pp. 459, 460).— The 

 method is essentially the same as that described in a method for determining 

 uric acid in blood (E. S. R., 41, p. 13). The preparation of solutions required 

 and the technique of the method are described in full. 



A simplified macro-Kjeldahl method for urine, O. Folin and L. E. Weight 

 (Jour. Biol. Chem., 3S (1919), No. 3, pp. 461-^64, fig. 1).—A simplified macro- 

 Kjeldahl method for the determination of nitrogen in urine is described, whicli 

 requires very little equipment and by means of which it is stated that a urinary 

 nitrogen determination can be finished in from 20 to 25 minutes. The technique 

 is as follows : 



To 5 cc. of undiluted urine in a 300 cc. Kjeldahl flask are added 5 cc. of the 

 phosphoric-sulphuric acid mixture previously described in connection with the 

 micromethod (E. S. R., 41, p. 13), 2 cc. of 10 per cent ferric chlorid solution, 

 and from 4 to 6 small pebbles. The mixture is boiled vigorously for 8 or 4 

 minutes over a microburner until dense white fumes appear. The mouth of the 

 flask is covered with a small watch glass, and the heating continued vigorously 

 for 2 minutes and gently for 2 minutes longer. The flame is removed and the 

 flask cooled for not more than 5 minutes, after which 50 cc. of water and then 

 15 cc. of saturated sodium hydroxid are added, and the flask is connected 

 promptly by means of a rubber stopper and ordinary glass tubing with a re- 

 ceiver containing from 35 to 75 cc. of N/10 acid, a drop or two of alizarin red, 

 and water to make a total volume of 1.50 cc. The flask is again boiled for 4 or 

 5 minutes, after which the contents of the receiver are titrated to a faint red 

 without cooling. 



It is stated that the simplified distillation process is applicable to other 

 determinations involving the removal of ammonia. The destructive digestion 

 process is not applicable to highly resistant material, such as milk or urines 

 containing much sugar, unless fuming sulphuric acid be used in place of the 

 ordinary acid. 



Vinegar making from apples, S. F. Anderson (Jour. Agr. [New Zeal.}, 18 

 (1919), No. 4' PP- 218-220, figs. 2). — Directions are given for making cider 

 vinegar on a small scale. The author recommends for final clarification treat- 

 ment with isinglass, whites of eggs, or Spanish clay, and filtration through 

 flannel. 



A fermentation process for the production of acetone and ethyl alcohol, 

 J. H. NoKTHKOP, L. H. Ashe, and R. R. Mokgan (Jour. Indus, and Engin. Chem., 

 11 (1919), No. 8, pp. 723-727, figs. 2).— The method described, which is protected 

 by U. S. Patent 1,293,172 dedicated to public use, consists of the fermentation 

 of a dilute solution of molasses with the production of ethyl alcohol and acetone 

 by means of a culture of an organism to which the name Bacillus acetoethylicum 

 has been given. The general characteristics of the organism, together with the 

 optinmm conditions for its growth, are summarized and the details of the 

 process of fermentation described. 



The optimum H-ion concentration was found to be from pH 8 to pH 6, 

 which could be maintained by the addition of lime to the fresh mash. The 

 fermentation when conducted on an experimental scale was complete in from 

 50 to 60 hours, with a yield of from 8 to 8.5 per cent of the sugar as acetone, 

 and from 20 to 21 per cent of alcohol, mostly ethyl, but with traces of propyl 

 and butyl alcohols. The fermentation may be made continuous in a fermenting 

 tank filled with some inert substance, such as coke or beech shavings covered 

 with a culture of the organism, by adding the fresh mash at the bottom and 

 allowing the fermented mash to run off at the top. 



