52 CHEMICAL STATICS 



The addition of the acid causes a flocculent precipitate to appear 

 and the mixture turns dark brown. Two and one-half litres of 

 ether are then added to each bottle and the contents shaken 

 thoroughly until they attain an oily consistency. Rubber stop- 

 pers with two perforations are then fitted into the necks of the 

 bottles. Through one perforation is inserted a long glass tube 

 reaching to the bottom of the bottle, to act subsequently as an 

 air inlet, and through the other is inserted a short tube just reach- 

 ing to the bottom of the stopper and provided with a rubber 

 tube and pinch-cock. The stoppers are then tied down and the 

 bottles quickly inverted and allowed- to stand at room tempera- 

 ture for twenty-four hours. By this time the contents of the 

 bottles, if the temperature of the room is not too warm, should 

 have separated into two layers, an upper, jelly-like, very deeply 

 colored ether layer containing the greater part of the hsematin 

 hydrochloride, and a lower, aqueous layer containing the globin 

 to some extent contaminated by hsematin hydrochloride. The 

 latter is then drawn off through the shorter of the two tubes 

 inserted through the stopper.* 



To this fluid is added four volumes of a mixture of equal parts 

 by volume of alcohol and ether. A light-colored precipitate is 

 obtained, leaving the fluid very deeply colored. This precipi- 

 tate is collected upon a hardened filter, washed once with a volume 

 of alcohol equal to that of the watery fluid from which it was 

 precipitated, drained and then scraped off the paper and dissolved 

 in a volume of JV/10 HC1 equal to that of the fluid from which 

 the globin was precipitated. This solution is now diluted by 

 the addition of three times its volume of distilled water, and 

 20 per cent ammonia solution is carefully added until a precipitate 

 just appears. One cubic centimetre of strong ammonia per litre 

 is then added and the dense, flocculent precipitate is collected 

 on a filter. The precipitate is then washed in large volumes of 

 absolute alcohol, alcohol-ether mixture and ether. After drain- 

 ing in a dry atmosphere (preferably within an incubator over 

 H 2 SO 4 ) the precipitate is allowed to dry for 24 hours in an incu- 

 bator over H 2 S04, then pulverized and sifted and returned to the 

 incubator to dry over H 2 SO 4 for one week. 



* The separation of the fluid into two layers is sometimes very slow. In 

 such cases separation may be hastened by centrifugalization. 



