323 



The contents of the still are now either a clear liquid or — more 

 frequently — a fat is floating on the surface and a resin has subsided. 

 Pour off from the latter and remove the fat by filtering through a 

 wet filter. 



All these three substances — resin, fat, aqueous liquid — together 

 with the remaining substance, have to be examined separately. 



(a) The resinous mass is usually of a dark colour. Wash with 

 water and try if it contains an alkaloid by triturating it assidu- 

 ously with Avater containing l-20tli of its weight hydrochloric acid 

 of 1.12 specific gravity, keeping at ordinary temperature for a few 

 hours (heat applied with the acid is liable to split up the resin), 

 filter the acid watery solution and wash the resin well with water. 



a. Evaporate the acid liquid at a very gentle heat, try any crys- 

 talline or non-crystalline residue with the pi-oper tests (II., B, a) 

 and see, if it be a new or a known alkaloid. 



ß. The resinous mass, remaining in a, is compared with the 

 resin obtained previously (II., Ä and III., B), and the knowledge 

 of the latter is, if necessary, completed by means of the resin now 

 obtained. 



(b) Submit the fat to the same ti'eatment with hydrochloric acid 

 and water as the resin, examine the acid liquid for alkaloids, compare 

 the fat with the fat obtained previously (II., A, B), and complete 

 its investigation by means of the new material. 



(c) Over-saturate a small sample of the aqueous solution of in- 

 variably acid i-eaction with ammonia. If a precipitate is obtained 

 hereby, precipitate the whole liquid with ammonia. If no precipi- 

 tate has been obtained with ammonia, try in the same way suc- 

 cessively carbonate of ammonia, ley of potash (or of soda) and 

 carbonates and bicarbonates of potash or of soda. 



a. Let the jirecipitate, obtained by means of the above tests, 

 subside, wash, diy, triturate, digest with alcohol of 90%, wai-m, 

 filter, evaporate the alcohol and examine any remnant on al- 

 kaloids (II., B, a). 



ß. Precipitate the liquid remaining in c, after it has been made 

 slightly acid with acetic acid, or the original clear liquid, in case 

 no precipitate has been jjroduced by alkalies, with acetate of lead 

 completely and proceed according to II., B, e. The chief object 

 is in this case the investigation of non-volatile organic acids and 

 the completion of the former investigations. 



{d) The remaining mass, exhausted by alcohol of 45%, contains 

 most of the gum, and may be used for determining this substance 

 if the former investigations (IV.) have been without a satisfactory 

 result. For this purpose spread it on shallow dishes to drive 

 off the alcohol, mix with cold water, strain after some time, press, 

 let the liquid subside, decant, evapoi'ate to a small bulk, and 

 throw down the gum by means of alcohol, ifcc, according to 

 the instructions given under " Gum," p. 99. 



