Kanematsu Sugiiira and K. George Falk 2i 



Two samples of 0.0251 gm. each of substance in 50 cc. o£ water, 

 precipitated with 3 cc. of iodine sol., treated similarly, reqtiired 17.80 

 and 17.64 cc, respectively, of the thiosulfate sol., corresponding to 

 0.0242 gm. and 0.0239 gm. respectively of original substance. 



A series of experiments, in which the nitrogen was determined in 

 the filtrate f rom the tetraiodine Compound, gave the f ollowing data : 



0.0502 gm. of hexamethylenetetramine in 25 cc. of water, pre- 

 cipitated with 8.5 CC. of iodine sol., gave 1.8 mg. of nitrogen in the 

 filtrate. In 50 cc. of water, 2.9 mg. were found; and in 100 cc, 

 4.1 mg. The same amount of iodine sol. was used in each ex- 

 periment. 



The results of further test-analyses will not be given here, only 

 the conclusions drawn therefrom. 



The error in the estimation of hexamethylenetetramine in aque- 

 ous sol. is at most 15 percent of the amount present; but, as a rule, 

 it is much less. In urines, a compensation of errors apparently 

 occurs and the accuracy of the results is greater, perhaps within 5 

 percent of the amount present. Although this is not a very satis- 

 factory degree of accuracy for analytical work, it is sufficient for 

 the purpose in view; that is, for the determination of the amounts 

 of hexamethylenetetramine eliminated by the body under various 

 conditions.^ 



Very often, in the precipitation of urines with iodine sol., the 

 tetraiodine Compound forms fine needles. If a qualitative Identifi- 

 cation of the substance is desired, a recrystallization from Chloro- 

 form with production of the characteristic, mahogany-red, mono- 

 clinic crystals suffices. In the recrystallization, about 25 percent 

 of the substance is lost, so that in this way, a rough idea of the 

 amount originally present may be obtained. 



3 The results obtained so far in this part of the investigation will be pre- 

 sented in the Journal of Pharmacology and Experimental Thcrapeiitics, January, 

 1916. 



