10 TECHNICAL, DKUG STUDIES. 



The results obtained by this procedure will be found in the column 

 headed "Gasometric analysis, volume of oxygen evolved by MnO 2 ." 

 The potassium permanganate method was carried out in the manner 

 just described, except that the dilute sulphuric acid and dilute dioxid 

 solutions were placed in a generating flask and sufficient half-normal 

 potassium permanganate solution was added from a burette to give 

 a pink color to the solution. The figures obtained by this procedure 

 will be found in column marked "Gasometric analysis, volume of 

 oxygen evolved by K 2 MnO 4 ," and were made between January 14 

 and February 12, 1908. The results obtained by the two gaso- 

 metric methods are fairly concordant, but in general are less reliable 

 than those given by the iodin and official methods, being too depend- 

 ent on slight variations in temperature, pressure, leakage, and other 

 factors. 



In order to determine the rate of decomposition, the samples were 

 reexamined for percentage of hydrogen dioxid by the pharmaco- 

 poeial method at the expiration of 3, 6, 10, and 12 months after the 

 initial analysis. These results are also recorded in the accompany- 

 ing table. After determining the percentage of hydrogen dioxid 

 in the various brands by the methods outlined, they were examined 

 for preservatives, acidity, nonvolatile matter, fluorids, arsenic, 

 barium, etc. 



PRESERVATIVES. 



The principal labels on the packages, as well as the analytical 

 results obtained, show that a large proportion of the hydrogen 

 dioxid solutions contained small quantities of acetanilid. The 

 acetanilid was determined by shaking a 50 cc sample of hydrogen 

 peroxid twice with ether and once with chloroform, combining the 

 several extracts in a tared beaker and drying at 75 C. 



Experiments made with samples of hydrogen peroxid containing 

 known quantities of acetanilid showed that this method removed 

 about 95 per cent of the amount present. The acetanilid was iden- 

 tified by its physical and chemical properties, the iodin-phenol reac- 

 tion proving to be the most satisfactory. Tests were also made for 

 boric acid and borax with negative results. 



A number of samples found to be free from acetanilid possessed 

 a noticeable odor of aldehyde after being kept for some time. It 

 was suspected that alcohol had been used as a preservative, but dis- 

 tillation from both acid and alkaline media failed to give a distillate 

 in which alcohol could be detected by the iodoform test. By apply- 

 ing the method directly to the sample, however, good results were 

 obtained. The distillate from these gave the general reactions for 

 aldehyde with fuchsin and sulphurous acid and with Tollen's reagent. 

 The presence of fluorids was indicated ui several products, but the 



