THE CLEAVAGE OF PROTEINS WITH ALKALI 107 



mercury with hydrogen sulphide from their respective 

 precipitates and filtrates, the protein reactions are given 

 by the filtrates, and here also is found the poison in each 

 case. From 10 to 15 per cent, of the crude poison can be 

 precipitated by the use of platinum chloride in either water 

 or alcoholic solution. All attempts to crystallize this 

 precipitate failed, as only a small part of it is dissolved by 

 hot water, and the insoluble part is unaffected by any of 

 the ordinary solvents. The protein reactions are given 

 by the platinum precipitate, by both soluble and insoluble 

 parts, but not by the filtrate. The poison is found in the 

 insoluble part of the precipitate after removal of the plati- 

 num by hydrogen sulphide, its toxicity being markedly 

 increased. The other parts, after removal of the platinum, 

 are inert. 



The most active products have been obtained by precipi- 

 tation from solution in absolute alcohol with alcoholic solu- 

 tions of the chlorides of platinum, mercury, and copper and 

 removal of the base from the precipitate with hydrogen 

 sulphide. By this method we have obtained a body which 

 kills guinea-pigs of from 200 to 300 grams' weight in doses 

 of 0.5 mg. given intravenously. 



From a water solution of the poison, bodies giving protein 

 reactions may be salted out by the addition of ammonium 

 sulphate or sodium chloride to saturation, but in neither 

 case is the separation complete, the filtrates still responding 

 to the protein color tests after removal of the neutral 

 salts. In case of salting out with ammonium sulphate, the 

 solubility of both parts is thereby lessened and the toxicity 

 diminished, possibly on account of decreased solubility, 

 though both parts exhibit some poisonous action, and like- 

 wise both show the protein color tests. 



Phosphotungstic, phosphomolybdic, and picric acids all 

 give abundant precipitates. Since these reagents are also 

 used in the precipitation of alkaloidal bodies, the precipitates 

 .with phosphomolybdic and phosphotungstic acids were 

 further examined, the possibility suggesting itself that the 

 toxic body might be alkaloidal in nature, and that the 



