CHEMISTRY. 743 



cc. was added to 175 cc. of fresh urine at first, and as the excess of chloroform, which 

 settled to the bottom of the flask, gradually diminished inure was added from time 

 to time to insure an excess of the preservative. Tins sample and one of equal size to 

 which preservative had not been added were stored in a cool place, the temperature 

 averaging 40 to 50°, and the total and ammoniacal nitrogen were determined at 

 intervals of 1, 2, and 10 days, 1 month, and approximately 2 months. 



In the case of both samples, there was no appreciable loss of nitrogen until theend 

 of the first month. In the case of the preserved urine, during the last month there 

 was a loss amounting to 1.77 per cent of the nitrogen originally present as compared 

 with 7.7 per cent in the sample without preservative. The formation of ammonia 

 was checked by the preservative, the increase being only 0.029 per cent in 2 months, 

 whereas in the case of the unpreserved sample it was 0.679 per cent, values which 

 indicate, in the author's opinion, that although chloroform checks a loss of nitrogen 

 it does not entirely prevent it. 



The possibility of measuring the loss of nitrogen in the preserved urine by adding 

 daily aliquot samples of normal acid or by drawing air from the flask containing the 

 urine through standard acid is spoken of. 



The determination of carbon and hydrogen in urine, F. Thompson {Penn- 

 sylvania Sta. Rpt. 1903, pp. 42-44). — In connection with respiration calorimeter 

 experiments with a steer (E. S. R., 15, p. 799), the changes which urine undergoes 

 on drying were studied. 



In the 4 experimental periods composite samples of 10 days' urine were collected 

 and preserved with a small amount of chloroform. Analyses were made of each 

 composite as soon as possible after it was collected, and again at an interval of 24 

 hours, or in one case 48 hours. Samples of the urine mixed with finely pulverized 

 and recently ignited copper oxid were placed in a platinum boat and dried in a 

 combustion tube, which passed through an ordinary water-jacketed air bath, the 

 temperature inside the tube being approximately 90° C. A quantity of dry air 

 was drawn slowly through the tube. Assuming that carbon dioxid and ammonia 

 were the end products of any decomposition which might take place, provision was 

 made for collecting the ammonia in standard acid and the carbon dioxid in soda 

 lime. Under these conditions the sample was found to be completely dried after 

 about 15 hours. When constant weight was reached it was transferred to a com- 

 bustion furnace and the ordinary carbon ami hydrogen determinations made. 



In every case the sample which was kept longer contained less total solids than 

 the other, and in every case except one the total solids of the older sample contained 

 a higher percentage of carbon and hydrogen. "These results would indicate that 

 there is considerable decomposition upon evaporation to dryness but that it varies in 

 amount, consequently yielding a residue of variable composition." It was also noted 

 that on drying, the older sample gave off more ammonia than the other in every 

 case, but that there was no such regular variation with the carbon dioxid produced. 

 "This would indicate that some decomposition was in progress in the urine at the 

 ordinary temperature, but since the presence of chloroform should prevent any bac- 

 terial action any such decomposition would arise from the action of enzyms. The 

 data presented are, however, not sufficient to completely establish this. 



"If the ammonia given off is taken as a measure of the urea decomposed it is 

 plainly evident that there is a decomposition of the non-nitrogenous matters present, 

 since from 50 to 80 per cent of the carbon dioxid found is in excess of that necessary 

 to combine with the ammonia to form urea." 



The results "would seem to fairly well establish the fact that there is a decompo- 

 sition of the nitrogenous as well as the uon-nitrogenous bodies present." 



The estimation of sulphuric acid in urine by means of alcoholic strontium- 

 chlorid solution, R. vox Lengyel {Arch. Physiol. IPfluger'], 104 {1904), No. 9-12, 

 pp. 514-518). — The author recommends the use of alcoholic; strontium-chlorid solution 

 for estimating sulphuric acid in urine, since the method is accurate and rapid. 



