PAET IV. 



THE PURITY OF ALCOHOL. 



In my work with the protein poison, I have 

 found it necessary to give attention to the 

 purity of the alcohol used and I have found the 

 alcohol imported from Germany (Kahlbaum's) 

 not always up to the standard. In fact, I have 

 found it cheaper and safer to take the ordinary 

 alcohol and distill it with quick lime. The fol- 

 lowing tests may be used in determining the 

 purity of alcohol. 



1. The specific gravity is determined by the 

 picknometer. 



2. It should be miscible in all proportions 

 without cloudiness with water, ether and chlo- 

 roform. 



3. It should not redden litmus even after four 

 hours' exposure. Kahlbaum's alcohol often 

 reddens litmus in a much shorter time. 



4. The evaporation of 50 c.c. should leave no 

 weighable residue. Some samples of Kahl- 

 baum's alcohol gave in this amount as much 

 as 1 mg. and some more. 



5. A mixture of 10 c.c. of the alcohol, 5 c.c. 



