thrown out when benzoyl chloride is shaken up with a pyridine solu- 

 tion of an extract of the gland. Fraenkel did not succeed in crystallizing 

 this benzoyl compound, nor did he attempt to decompose it in order 

 to ascertain whether it was in reality a benzoate of the blood-pressure- 

 raising principle. 



Methods of Decomposing the Benzoyl Compound 



A quick method always used by us as a qualitative test is as follows: 

 The compound is dissolved in as little concentrated sulphuric acid as 

 possible, crushed ice is slowly added, and the benzoic acid which has 

 been split off is shaken out with ether. On neutralizing the solution 

 we found it to give the reactions characteristic of aqueous solutions of 

 the medullary substance. We have not considered this method adapted 

 to the decomposition of large quantities of the product. 



Decomposition of this benzoyl product was effected by means of an 

 alcoholic solution of sodium alcoholate, and also with strong hydro- 

 chloric acid and alcohol, but these methods were found to be less 

 satisfactory in practice than the following, \vhich is the method on 

 which we now rely. The benzoyl compound is dissolved in glacial 

 acetic acid, the solution heated to near the boiling point, and an equal 

 volume of a 25 per cent solution of sulphuric acid actively boiling 

 is slowly poured into the hot acetic acid solution, the whole being 

 shaken meanwhile. The flask is now attached to a back-flow condenser 

 and heated on a small flame for about ten minutes. 



The solution is next diluted with water and allowed to cool, the 

 benzoic acid, which has been thrown out, is filtered off and the rest 

 is removed with the help of ether. 



Mixed with the benzoic acid which has been removed by filtration 

 is found a dark brittle substance which softens on the water-bath, and 

 which we assume to be a benzoyl compound of unknown composition 

 Avhich was apparently unaffected by the dilute sulphuric acid. On dis- 

 solving it in concentrated sulphuric acid and diluting with crushed 

 ice, the resulting fluid gives none of the reactions characteristic of 

 suprarenal extracts. 



After decomposing the benzoyl product with hot dilute sulphuric 

 acid and removing the benzoic acid thus split off, we next get rid of 

 the acetic acid by repeated partial evaporations, taking care not to 

 let the solution become too concentrated and thus perhaps injure the 

 active principle. After the removal of the acetic acid the sulphuric 

 acid is precipitated with the help of lead carbonate. The lead sul- 

 phate is removed and the filtrate is allowed to stand in vacuo over 



48 



