52 Kafisas Academy of Science. 



solved with no appreciable liquid residue ( absence of, or limit of, 

 hydrocarbons). 



Phenol. — If 1 c.c. of cresol be mixed with 1 c.c, of glycerin, a 

 clear solution should be produced, from which, on the addition of 

 1 c.c. of water, the cresol should completely separate ( absence of, 

 and distinction from, phenol). Phenol forms a perfectly trans- 

 parent solution with this glycerin and water solvent. 



Thymol Iodide, (CeHa.CHs.CsHT.OI)?. 



This article, which has much popularity, is an antiseptic, known 

 by the commercial name of aristol. It should be free from the 

 alkalies, free iodine, and foreign bodies. These are appropriately 

 tested for, but the one test of the pharmacopoeia, which will elimi- 

 nate many of the substitutes that have been marketed for this 

 favorite antiseptic, is the "limit of ash" test, which reads as fol- 

 lows : 



If 0.1 gm. of thymol iodide be thoroughly ignited in a porcelain 

 crucible, it should leave not more than 0.003 gm. of residue (limit 

 of ash ) . 



Vanillin, (CgHs.OH.OCHs.COH 4:3:1). 



This expensive, fragrant organic compound is very tempting to 

 the unscrupulous merchant as a substance to be very easily adul- 

 terated with such a substance as acetanilid; therefore an appro- 

 priate test is found in the pharmacopoeia to betray the presence of 

 this adulterant, which reads as follows : 



On warming 0.1 gm. of vanillin with concentrated alcoholic so- 

 lution of sodium hydroxide, adding chloroform, and again warming, 

 it should not give an odor of phenyl-isocyanide (absence of acetani- 

 lid). 



The author of this paper commented upon the various tests 

 mentioned, and not only showed their importance but gave his 

 personal experience in the employment of them. 



