26 TECHNICAL DBUG STUDIES. 



odor was noticed. In certain instances this test ran parallel with 

 the former one, in that samples which gave scarcely any color or 

 odor with sulphuric acid gave but a slight ethereal odor, but for 

 the most part the tests were entirely at variance, as will be noted on 

 examining the table on page 27. When simply heated on the steam 

 bath marked differences in odor were noted, four samples gave off 

 a slight odor of no particular character, two an aromatic odor, and 

 the remainder a fatty odor of varying intensity. 



A reaction was obtained showing a slight trace of sulphates in 

 five products, a trace of chlorids in two, and a reduction of silver 

 nitrate in five, this being very marked with one specimen; oxalates 

 were indicated in two samples from the same manufacturer; heavy 

 metals were shown hi three cases, while six gave no reactions for 

 metals or acids. 



Only one sample showed the presence of objectionable amounts of 

 arsenic, and this was of foreign make and labeled " arsenic free." 

 The Marsh test was rigidly applied to every glycerin in order to 

 determine how completely the arsenic had been eliminated; six 

 specimens gave no mirror, and the others, with the exception of the 

 one above mentioned, contained less than one part in a million. 

 It is of interest to note that of two samples submitted by one manu- 

 facturer one contained arsenic and the other did not. 



Satisfactory results seemed impossible with the pharmacopoeial 

 test using ammoniacal silver nitrate; reduction took place in every 

 instance, and it was apparent that no significant conclusions could be 

 drawn from its use. Accordingly it was abandoned for the test 

 described by Hager, with which better comparative results were 

 obtained. Five cubic centimeters of the sample were mixed with 5 

 cc of 26 per cent ammonia water and 5 drops of silver nitrate added; 

 the mixture was allowed to stand at the ordinary temperature in the 

 dark for 15 minutes and its appearance noted. There was no reduc- 

 tion of the silver nitrate in six cases, and a marked reduction in two, 

 the other samples being slightly colored. 



ANALYTICAL DATA. 



The investigation showed that glycerin could be produced which 

 would answer all of the pharmacopoeial requirements with the 

 exception of the ammoniacal silver nitrate test. It also showed 

 that although some glycerins gave off a fruity odor when treated 

 with alcohol and sulphuric acid, they were otherwise of good quality; 

 therefore the wording of this test should be modified in order to 

 include the disagreeable butyric odor as it now discriminates only 

 against a "fruity odor." 



<* Loc. cit. 



