operation was repeated a second time when a further slight precipitation 

 occurred, but on repeating a third time the solution remained perfectly 

 clear. The solution was precipitated with alcohol, washed free of chlor- 

 ides with dilute alcohol, alcohol and ether and dried in vacuum 

 over sulfuric acid. The substance was finally precipitated from about 

 1 per cent, hydrochloric acid with alcohol, filtered and washed free of 

 chlorides with dilute alcohol and then in alcohol and ether and dried in 

 vacuum over sulfuric acid. The dry preparation weighed about 66 

 grams. 



This crude acid salt was rubbed up in a mortar with about 500 cc. 

 of cold water, allowed to stand a few hours and then filtered and washed 

 with water, alcohol, and ether and dried in vacuum over sulfuric acid. 

 The water-insoluble residue weighed about 30 grams. 



The water-soluble portion contained in the filtrate was precipitated 

 with barium hydroxide and reserved for a future investigation. 



PREPARATION OF THE STRYCHNINE SALT 



The water-insoluble portion of the barium salt mentioned above 

 was suspended in water and the barium precipitated with slight excess 

 of dilute sulfuric acid. The barium sulfate was removed and the fil- 

 trate precipitated with excess of copper acetate. The copper precipi- 

 tate was filtered and washed with water until the washings gave no 

 reaction with barium chloride. It was then suspended in water and 

 the copper precipitated with hydrogen sulfide and the copper sulfide 

 filtered off. 



The solution containing the free organic phosphoric acid was 

 diluted to about 2 liters with water and heated on the water-bath and 

 44 grams of powdered strychnine added. After heating for a few 

 minutes the strychnine was dissolved. The solution was filtered and 

 concentrated in vacuum at a temperature of 45 to 50° to about one-half 

 of the volume. The strychnine salt soon began to separate in long 

 needle-shaped crystals. After standing in the ice chest over night the 

 crystals were filtered off and washed in ice cold water and finally in 

 absolute alcohol and ether and dried in the air. Yield 45.8 grams. 



For further purification the substance was twice recrystallized 

 from hot water. It was then obtained in pure white, needle-shaped 

 crystals which looked perfectly homogeneous. 



From more concentrated solutions the substance sometimes sep- 

 arates in the form of colorless plates which differ from the needle- 

 shaped crystals in that they contain about 4 per cent, more of water 

 of crystallization. 



The strychnine salt has no sharp or definite melting point. Heated 

 in a capillary tube it softens at about 200 C. but it does not melt com- 

 pletely even at a much higher temperature. On moist litmus paper it 



38 



