METHODS OF EXTRACTING PTOMAINES. 159 



iible in water and alcohol, and generally insoluble in ether, 

 and (2) the free alkaloids are soluble in ether, and are re- 

 moved from alkaline fluids by agitation with ether. These 

 principles are capable of great va,riety in their application. 

 The usual directions are as follows : Treat the mass under 

 examination with about twice its weight of pure 90 per 

 cent, alcohol, and from ten to thirty grains of tartaric or 

 oxalic acid ; digest the whole for some time at about 70°, 

 and filter. Evaporate the filtrate at a temperature not ex- 

 ceeding 35° either in a strong current of air or in vacuo 

 over sulphuric acid. Take up the residue Avith absolute 

 alcohol, filter, and again evaporate at a low temperature. 

 Dissolve this residue in water, render alkaline with sodium 

 bicarbonate, and agitate with ether. After separation re- 

 move the ether with a pipette, or by means of a separator, 

 and allow it to evaporate spontaneously. The residue may 

 be further purified by redissolving in water and again ex- 

 tracting with ether. 



The following modifications of this method are em- 

 ployed : Instead of tartaric or oxalic acid, acetic acid is 

 frequently used. 



When the fluid suspected of containing a ptomaine is 

 already acid from the development of lactic or other organic 

 acid, the addition of an acid is often dispensed with. 



Ether extracts are made from both acid and alkaline 

 solutions. 



Chloroform, amylic alcohol, and benzine are used as sol- 

 vents after extraction with ether. 



The modification of this method, as carried out by Selmi 

 and Maeino-Zuco is given in detail as follows : 



The material is divided as minutely as possible, placed 

 in a large flask, and treated with twice its volume of 90 per 

 cent, alcohol, and acidulated with tartaric acid in the pro- 

 portion of 0.6 gramme to 100 c.c. of the mixture, taking 

 care from time to time that the reaction is permanently 

 acid. The flask, which is connected with a reflux condenser, 

 is now placed on the water-bath and kept at the constant 

 temperature of 70° for twenty-four hours. While yet 

 warm the liquid is transferred to a special apparatus for 



