ALEXIN ABSORPTION. 401 



sis is complete in A in half an hour. The corpuscles in B are 

 intact after 3 hours; slight hemolysis subsequently takes place. 

 It is scarcely necessary to mention that control tubes A T and 

 B T, identical with A and B respectively, but containing non- 

 sensitized bovine blood, are likewise prepared; in these mixtures 

 there is no hemolysis. 



It is evident, then, that a small amount of normal serum inhibits 

 hemolysis distinctly; further experiments show that this antago- 

 nistic effect varies in intensity with the increase of heated normal 

 serum and the decrease of salt solution. 



The question arises as to how intense this antagonistic power in 

 normal serum is. We can also determine whether normal serum 

 combats one or both the factors of hemolysis (alexin and sensitizer). 

 We find that the serum shows a relatively retarding effect on alexin 

 even if the dose of it is relatively high. For example: 



Mixture A contains : 0.6 c.c. of salt solution,* 0.05 c.c. guinea-pig 

 alexin, and 0.2 c.c. of salt solution containing 40 per cent of sen- 

 sitized bovine blood. t Mixture B contains the same amount 

 of blood and twice as much alexin, but 0.6 c.c. of normal rabbit 

 serum, 56 degrees, in place of the salt solution. Hemolysis is more 

 rapid in A than in B. 



When corpuscles are heavily sensitized, however, the antihemo- 

 lytic effect of normal serum (56 degrees) is less evident, although 

 still distinct. In the following experiment even small doses of 

 serum show distinct effects: 



Tubes A and C. Each 0.7 c.c. of salt solution. 



Tubes B and D. Each 0.4 c.c. of salt solution plus 0.3 c.c. of 

 heated normal rabbit serum. 



To A and B is then added 0.25 c.c. of salt solution containing 

 40 per cent faintly sensitized ox blood (1 part of rabbit anti- 

 bovine sensitizer to 10 parts of blood) ; to tubes C and D is added 

 the same amount of blood sensitized with three times as much 

 sensitizer. To each of the four tubes is then added 0.05 c.c. of 

 guinea-pig alexin and the tubes are placed at 35 degrees. Hemoly- 



* In these experiments 0.9 per cent NaCl is used. 



f This blood is relatively well sensitized and is prepared as follows: To 1 c.c. 

 of washed blood is added 9 c.c. of salt solution and 0.5 c.c. of rabbit-antibovine 

 serum, 56 degrees. Contact, 1 hour. Centrifugalization and removal of the 

 supernatant fluid. 2.5 c.c. of salt solution is added to the sediment. 



