306 LEO LOEB. 



A I per cent, solution of potassium cyanide usually destroys 

 the efficiency of the fibrin inside of half an hour. After hav- 

 ing been kept for two hours in such a solution the fibrin be- 

 comes opaque. 



One cubic centimeter of a 2 per cent, solution of potassium 

 oxalate, or 5 drops of a 10 per cent, solution of the same solu- 

 tion added to 4 cc. of serum, entirely prevents the coagulation. 



One half cubic centimeter of a 2 per cent, solution of potas- 

 sium oxalate inhibits the coagulation markedly. 



The addition of 5 drops, or I cc., or 2 cc. of a 2 per cent, cal- 

 cium chloride solution had, in one series of experiments, a 

 slightly accelerating influence on the coagulation in comparison 

 with control experiments which were made with the addition of 

 i cc. of a weak sodium chloride solution. Calcium is probably 

 present in a sufficient quantity in the serum and the farther addi- 

 tion of it can no longer exert a pronounced influence. 



A more extended series of experiments on the action of differ- 

 ent salts on the coagulation is to be made later. Some experi- 

 ments have, however, already been made on the action of am- 

 monium chloride (the marked action of urea suggested these 

 experiments). This salt, compared with the corresponding solu- 

 tions of sodium chloride, has a specifically inhibiting action on 

 the coagulation. The addition of I cc. of a 16 per cent, solu- 

 tion of sodium chloride frequently had a weak, though at times 

 a somewhat stronger, inhibiting influence ; / drops of a 16 per 

 cent, ammonium chloride solution, or i cc. of a 4 per cent, solu- 

 tion of the same solution, had a much more pronounced inhibit- 

 ing influence. One cubic centimeter of a 16 per cent, solution 

 of acetamid had but a slightly inhibiting effect. The addition of 

 a few drops of ammonium prevented coagulation entirely ; this, 

 however, was probably merely an alkali-action. 



If the mixtures of blood serum with the above substances are 

 kept for 24 hours in a warm room, putrefaction of the liquid 

 usually takes place. This putrefaction does not prevent coagu- 

 lation although it may inhibit it somewhat. 



After the second, gelatinous, coagulation has taken place, it is 

 possible to separate a second serum from this coagulum. This 

 second serum, to which fresh shreds of fibrin have been added, 

 no longer coagulates. 



