I9I3] Alfred P. Lothrop 467 



phenol-globules rapidly collect in a clear oily layer on the surface of 

 the milky aqueous Solution. Pour the mixture into a separatory funnel 

 and, after it has remained there undisturbed for about a half-hour, 

 isolate the oily phenolic extract of urochrome by drawing off the 

 underlying liquid. An equal volume of ether is added to the phenolic 

 extract, with which the ether mixes homogeneously. This liquid is 

 then treated with an equal volume of water. Two layers form at once. 

 The mixture is shaken very gently, in order to encourage transfer of 

 the urochrome to the water layer but to prevent undue emulsion of the 

 oily extract. Practically all the pigment passes promptly into the un- 

 derlying aqueous Stratum, which is drawn off after a suitable interval. 



Under Dr. Gies' guidance I have endeavored to ans wer his ques- 

 tion : Does the aqueous Solution of urochrome, as prepared by the 

 foregoing method, contain (or yield) uroerythrin? For this pur- 

 pose colorless sodium urate was dissolved in such urochrome ex- 

 tracts prepared from both human and dog urines, the resulting 

 Solutions were acidified for the Separation of uric acid, and the 

 deposited crystals of uric acid were examined microscopically for 

 uroerythrin. All the crystals thus obtained were colored in the 

 familiär way with uroerythrin, as when separated from normal urine. 

 Experiments on the use of other solvents than phenol for the extrac- 

 tion of urochrome from urine, on the relationship of uroerythrin to 

 urochrome, and on a number of suggestions from the results, will 

 be described later. (The method was demonstrated. ) 



84. Comparison of methods for the preparation and de- 

 termination of cholesterol. Joseph S. Hepburn. Cholesterol, 

 extracted from brain, has been purified by saponification either with 

 sodium ethylate at room temperature or with boiling alcoholic pot- 

 ash, in each case followed by crystallization from ether. Cholesterol 

 has also been prepared from gall stones by extraction with ether and 

 crystallization from that solvent. 



The melting points of six samples from brain, 148.4-149.1°, of 

 two samples from gall stones, 147.4°, and of various mixtures of 

 two samples (50 per cent. of each sample), 147.7-148.0°, demon- 

 strate the identity of the cholesterol products from the two sources. 

 The melting points of the samples and of their mixtures also show 

 that neither heat in the process of saponification nor alkaline re- 

 agents, such as alcoholic potash and sodium ethylate, produce any 

 rearrangement of the cholesterol molecule. 



