1887.] Proteids of the Seeds of Abrus precatorius. 333 



dissolved out a proteid. This proteid is an albumose. The chloride 

 of sodium method may be used instead of the ammonium sulphate; it 

 'takes a longer time, but gives products freer from colouring matter. 



For chemical examination, the albumose is readily prepared by 

 boiling and filtering an aqueous infusion of the seed. The globulin 

 ■is coagulated while the albumose remains in solution. 



Properties of the Globulin. 



1. It is insoluble in distilled water, but readily soluble in 10 to 15 

 per cent, sodium chloride or magnesium sulphate solution ; soluble to 

 a less extent in 5 per cent, sodium chloride solution, and scarcely at 

 all in 0'75 per cent. 



2. It is completely precipitated from solution by saturation with 

 sodium chloride after slightly acidifying, and with ammonium 

 sulphate, whether the solution be neutral, acid, or alkaline. 



3. It is coagulated by heat in 10 per cent, magnesium sulphate 

 -solution, between 75° and 80° C, the liquid being made distinctly 

 acid; in 10 per cent, sodium chloride, between 66° and 73° C. 



4. When the solution in 10 per cent, sodium chloride is placed in 

 the incubator at 35° to 40° C, and allowed to remain twenty-four or 

 -even forty-eight hours, no precipitation occurs; a reaction in. marked 

 contrast to that given by some vegetable globulins. In its high 

 •coagulation temperature, and in its non-precipitation from solution by 

 prolonged exposure to a moderate heat, abrus-globulin agrees with the 

 proteid I have described in the juice of the fruit of Garica papaya, 

 which, from its resemblance to serum-globulin, I have called vege- 

 table paraglobulin.* The vegetable myosins occurring in the cereals, 

 wheat, rye, and barley, have a lower coagulation temperature than the 

 paraglobulins, viz., 50° — 55° C.,and are precipitated from solution and 

 rendered insoluble by a prolonged exposure to a temperature of 35° — 



40° at 



Properties of the Albumose. 



1. Soluble in cold or boiling distilled water. Its chemical and 

 physical properties are not apparently altered by boiling its solution. 



2. It is not precipitated from solution by saturation with sodium 

 •chloride unless a large excess of glacial acetic or phosphoric acid be 

 kidded. It is readily precipitated by saturation with neutral ammo- 

 nium sulphate. 



3. It does not form an albuminate. 



4. Nitric acid does not precipitate it in a watery solution ; but a pre- 

 cipitate falls if solid sodium chloride be added nearly to saturation. 



* " Nature of Papain, &c," ' Journ. of Physiol.,' vol. 6, p. 353. 

 f ' Physiol. Soc. Proc.,' Feb. 12, 1887. 



2 b 2 



