164 COLLECTED STUDIES IN IMMUNITY. 



Although we can entirely confirm these statements, we cannot accept 

 Matthes' view, according to which the solution of the fixed blood- 

 cells by pancreatin is conceived as a digestion, the Hay em solution 

 acting somewhat like an immune body. The striking fact that 

 the fixed blood-cells dissolve even in their own serum appeared 

 to us rather to be the result of the union of the mercuric chloride 

 (which adhered to the blood-cells and prevented this solution) with 

 the albumin of the serum. The experiments made in this direc- 

 tion at the suggestion of Prof. Ehrlich have completely confirmed 

 this view. 



Following the procedure of Matthes, I employed rabbit blood 

 which, freed from serum, was mixed with Hayem's solution in the 

 proportion of 1:4. After standing a short time, the blood was cen- 

 trifuged and then washed three or four times with 0.85% salt solu- 

 tion. Finally a 5% suspenson of the fixed blood-cells in .85% 

 salt solution was prepared. The corresponding control was made 

 with normal 5% rabbit blood. 



In the experiments 1 cc. of the 5% blood mixtures was used; the 

 fluid, after the addition of the reagent being made up to 2 cc. with 

 physiological salt solution. It was found that not only fresh rabbit 

 serum, but even rabbit serum which had been inactivated by half an 

 hour's heating to 56 C., as well as rabbit serum which had been diluted 

 with ten volumes of physiological salt solution and then boiled one hour, 

 was still able to cause solution of the fixed rabbit blood-cells; 0.075 

 cc. serum causing complete and almost instantaneous solution. In 

 this case the toxic action of the serum can hardly be thought of. 

 The experiment indicated rather that other kinds of influences are 

 the cause of this curious phenomenon. If the conception is correct 

 that we are dealing with a combination of the mercury with the 

 serum, it should be possible also, with other means which abstract 

 the mercury, to cause a solution of blood-cells fixed with Hayem's 

 solution. As a matter of fact this can very easily be done. I chose 

 potassium iodide and sodium hyposulphite for this test and found 

 that extremely small amounts of these substances cause immediate 

 solution of the fixed blood. 0.00075 cc. of a 20% KI solution in 

 physiological salt solution or 0.00025 cc. of a similar hyposulphite 

 solution sufficed to completely dissolve 1 cc. of our 5% fixed blood 

 suspension. 1 This positively shows that the function of the serum 



1 With normal rabbit blood, 1000-2000 times the amount of KI or of hypo- 

 sulphite solution still acts indifferently. 



