alcoholic fluid is then filtered and the gieater part of the alcohol re- 

 moved by distillation; the remainder is driven off on the water-bath. 

 The entire removal of the alcohol is necessary, and in order to avoid 

 too great concentration of the acid fluid, which seems to destroy some 

 of the active principle, water has now and then to be added. The 

 brownish fluid when filtered gives all the well-known reactions char- 

 acteristic of Vulpian's chromogen, and on neutralizing the sulphuric 

 acid we found the filtrate to be physiologically very active. 



This filtered fluid is next treated with the proper quantity of 

 benzoyl chloride and sodium hydrate according to the Baumann- 

 Schotten method of forming a benzoyl compound. There results a 

 tarry substance of a light yellow color which sticks to the sides of the 

 separator funnel and which is collected and washed until the wash 

 fluid no longer gives an alkaline reaction. It is next dissolved as far 

 as possible in alcohol and the alcohol evaporated. The residue is 

 then treated with ether, which takes up the greater part of it, the 

 ethereal solution is filtered and the ether driven off. 



The residue, ^vhich is of tarry consistence and amber color, is 

 taken up in strong alcohol from which all basic substances have been 

 removed by distilling from tartaric acid. It is then boiled for two hours 

 with animal charcoal previously well washed with purified alcohol. 

 After filtration and the evaporation of the alcohol a considerable 

 quantity of crystalline residue is obtained which is found to consist 

 of the benzoyl compound of the active principle contaminated with 

 other benzoyl derivatives and which \\'e may call the crude benzoyl 

 product. It is insoluble in ^vater, alkalies or acids of ordinary strength, 

 is soluble in alcohol, ether, glacial acetic acid and concentrated sul- 

 phuric acid. 



It is of interest in this connection to note that benzoyl chloride 

 effects the complete removal of the blood-pressure-raising constituent 

 from an aqueous solution. This is proved by the fact that the filtrate 

 from the insoluble benzoate no longer gives the characteristic chemi- 

 cal reactions of the active principle, and that chemical manipulations 

 no longer yield a blood-pressure-raising constituent. Indeed, an injec- 

 tion of a sufficient amount of the material left after the sodium benzo- 

 ate and the excess of alkali have been removed, causes a sharp and 

 sudden fall of pressure instead of a rise. 



It was not until long after we had made use of benzoyl chloride as 

 a precipitant of the active principle that we obtained access to 

 Fraenkel's* paper. From it we learned that a syrupy substance is 



* Wien. med. Blatter, 1896, No. 14-16. 



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