ANHYDROUS PRUSSIC ACID. 121 



Atropin. — Rebourdain (Comptes Rendus, 1850) gives the 

 following process for the ready preparation of atropin. Fresh 

 belladonna leaves are to be bruised, the juice extracted by 

 pressure, heated to 176°-19'4:° F. and filtered. When the 

 filtrate has cooled, 4 grm. caustic potassa and 30 grm. chloro- 

 form per quart are added, and the whole well shaken together. 

 After an hour's repose, the chloroform, holding in solution the 

 atropin, subsides as the lower stratum, and after decantation 

 of the supernatant liquid, is to be washed repeatedly with 

 water. The chloroform solution is then distilled over a water- 

 bath. The residue in the retort, by digestion with dilute sul- 

 phuric acid, yields the atropin. This solution, on treatment 

 with carbonate of potassa, drops the atropin, which may be 

 obtained in acicular crystal by resolution in alcohol and spon- 

 taneous evaporation. 



Pyrotartaric Acid. — According to Arppe (Liebig's Anna- 

 len, Ixv.) pyrotartaric acid may be prepared by distilling 

 together, in a capacious green-glass retort, a mixture of equal 

 parts of powdered crystals of tartaric acid and pumice-stone 

 dust. For 2ft) acid, the time required is 12 hours. The dis- 

 tillate is to be mixed with water, the supernatant empyreumatic 

 oil separated by the aid of a funnel, and the liquor gently 

 evaporated and set aside. The cryst^ine mass which forms 

 is to be pressed between paper, and then spread upon papers 

 saturated with alcohol in order to remove the empyreumatic 

 and coloring matters. The product amounts to 7 per cent, 

 of the acid employed. 



Anhydrous Prussio Acid. — Wohler (Central Blatt, 1850) 

 gives the following process for preparing anhydrous prussic 

 acid. 10 pts. prussiate of potassa, 7 pts. sulphuric acid, and 

 14 pts. water are mixed together in a retort and distilled over 

 an open charcoal fire. The neck of the retort should be raised 

 to an angle of 45° and occasionally cooled, so as to condepse 

 and drive back the aqueous vapor, and thus prevent its passing 

 over into the drying-tube attached, containing the chloride 

 of calcium. Between this latter tube of U shape, there should 

 be another vessel containing a small quantity of chloride of 



