76 REACTION OF CELLS 



The radio-active substances decompose according 

 to the same law. This law is evidently of very far- 

 reaching importance. 



There is no doubt that the different cells in a sample 

 of bacteria or red blood-corpuscles possess a different 

 power of resistance to deleterious substances. We 

 may, as an instance, take the red blood-corpuscles, 

 which have been most closely examined. If we 

 add different quantities of a poison, e.g. vibriolysin, 

 to an emulsion of i-6 per cent horse erythrocytes in 

 10 cc. of physiological salt-solution (0-9 per cent 

 NaCl) and keep the mixture at 2>7° C. for two hours, 

 we find that no action is observed until more than 5 

 cubic millimeters of the poison is added. With the 

 doses indicated we obtain the degree of haemolysis 

 given below : 



Cubic mm. of poison : 5 10 20 30 40 50 60 70 80 90 100 no 

 Degree of haemolysis : o 06 4 16 34 52 67 78 86 93 98 100 



This table gives the sensibility of the erythrocytes, 

 25 per cent are killed by 35 c.mm., 50 per cent by 

 49 c.mm., 75 per cent by 67 c.mm. and no cell 

 resists 1 10 c.mm. 



From two different series I have calculated the 

 relative number of erythrocytes of a certain sensi- 

 bility and constructed a curve giving the frequency 

 of the erythrocytes of a certain sensibility, where 

 the maximum is placed above the value 4 of the 

 abscissa. The zero-point is placed on the ordinate 

 10 (upper curve on Fig. 22). Below this curve 

 the ordinary curve of probabilities (e.g. for the fre- 



