32 TECHNICAL DRUG STUDIES. 



SCHERING & GLATZ. 



* * * We had lengthy correspondence with Messrs. Schering in 1905 and 1907, 

 relative to their glycerin, and they reported that their product complies with every 

 test of the U. S. Pharmacopoeia, save that for fatty acids. This test they consider 

 extravagant and impossible to comply with, therefore labeling their product, as per 

 specimen inclosed: "Schering's glycerin, thrice distilled, complies with every test of 

 tie U. S. Pharmacopoeia, excepting the one for volatile fatty acid, which is not made 

 by the pharmacopoeia of any other country. While this test may show the presence 

 of minute quantities of fatty acids, these are so infinitesimal that they are wholly 

 without significance. No glycerin, so far as we know, responds to this test." 



Reverting to your esteemed communication of the 10th ult., we would say that the 

 Chemische Fabrik auf Action (vorm. E. Schering) in Berlin, beg to comment as 

 follows on your findings relative to their glycerin: 



"Slight odor on heating at temperature of water bath. It is not stated that the odor 

 noticed was an unpleasant one. Doubtless most products will show an odor upon 

 warming, no matter how pure and how odorless in the cold state. 



"Slight fatty ethereal odor on warming with alcohol and sulphuric acid. Minimal 

 traces of fatty acids are contained in every distilled glycerin. Our repeated request 

 to send us any glycerin which is absolutely free from fatty acid, you have not been 

 able to comply with. 



" Yellow color with slight fatty odor when mixed with an equal volume of sulphuric acid 

 in the cold. A yellowish coloration on mixing glycerin with concentrated sulphuric 

 acid is unavoidable and has been declared admissible by the U. S. Pharmacopoeia. 



" Traces of heavy metals. It may be conceded that our glycerin contains traces of 

 heavy metals. So long as vessels made of heavy metals are used, this will not be 

 preventable. But the method of test of the U. S. Pharmacopoeia is of such a nature 

 that discoloration upon addition of hydrogen sulphid may also be due to the presence 

 of organic substance, or the glycerin itself. 



"Arsenic. It has not been found possible in our analytical laboratory to demonstrate 

 in unequivocal manner the presence of arsenic in our chemically pure glycerin. But 

 if the finding of '0.4 part per million' is correct, the glycerin abundantly fulfils the 



ro visions of the U. S. P. on this point. 



"Reduces with ammoniacal silver nitrate, U. S. P. test and Eager' s directions. Regard- 

 ing the behavior of ammoniacal silver solution to glycerin a great deal has been pub- 

 lished, but the matter is still unclear. Inasmuch as refined glycerins, which are far 

 less pure than distilled glycerins, do not reduce, the test is generally not considered 

 of importance. 



"Reduces with Fehling's solution. It would be interesting to learn how this test was 

 made. Inasmuch as Dr. Wiley's analysis showed no sugar and as we ourselves know 

 that none is present, we do not understand the object of the test. That glycerin is a 

 readily oxidizable body and therefore has a reducing action, must, of course, not be 



overlooked." 



CONCLUSIONS. 



It appears from this investigation that a high grade glycerin should 

 meet the following requirements : 



Its specific gravity should be about 1.250 at 25 C. 



It should be neutral to litmus paper. 



It should leave no ash on ignition. 



It should give off but a slight odor when heated alone at the tem- 

 perature of the water bath. 



