DEVIATION OF THE ALEXIN IN HEMOLYSIS. 359 



5. This last paragraph is applicable to certain recent researches 

 of Sachs* on the so-called " anticomplement " power of normal 

 sera. For the discussion of these experiments we may refer to the 

 previous article. Pfeiffer and Fried berger have also observed 

 certain analogous facts with bacteria, and it would seem as if their 

 work might be explained in a similar manner. 



We shall now consider more attentively the experimental results 

 to which reference has been made in paragraphs 2 and 3 above. 

 We have seen, first, that the albuminous substances precipitated by 

 a specific serum are in reality sensitized, or, in other words, able to 

 absorb alexin, and, secondly, that small amounts of precipitinogen 

 suffice to form an abundant precipitate with the precipitin serum. 

 We must further emphasize that a relatively large amount of this 

 precipitin serum is necessary to cause a precipitum sufficient to 

 fix alexin well. The following experiment indicates the relation 

 between the two sera, the precipitum obtained, and the degree of 

 alexin absorption. As precipitinogen, ox serum is used, and, as 

 precipitin, the serum of a rabbit immunized against ox blood and 

 heated to 55 degrees.! 



Tube 1. Ox serum, 55 degrees 0.025 c.c. 



Serum rabbit > ox, 55 degrees 0.1 c.c. 



NaCl solution (0.85 per cent) 1.9 c.c. 



Tube 2. Ox serum 0.025 c.c. 



Serum rabbit > ox, 55 degrees 0.6 c.c. 



NaCl solution 1.4 c.c. 



Tube 3. Ox serum 0.025 c.c. 



Serum rabbit > ox, 55 degrees 2.0 c.c. 



These three tubes contain the same total volume and the same 

 amount of ox serum. They differ in their respective amounts of 

 precipitin serum, which in the small doses is replaced by salt solu- 

 tion, so that the total volumes are the same. Three control tubes 

 (4, 5 and 6) are also prepared corresponding to tubes 1, 2 and 3 

 respectively, but containing salt solution in place of ox serum. 

 After one-half hour at 37 degrees there is no evident precipitate 

 in tubes 1, 4, 5 and 6; there is a distinct though slight precipitate 

 in tube 2; and in tube 3 there is a voluminous precipitate. 



* Deutsche med. Woch., 1905, No. 18, 705. 



t This serum, for the sake of abbreviation, is referred to as " Sorum rabbit > ox. '* 



