THE PRECIPITINS AND THEIR ANTIBODIES 



I c.c. of the first serum was equivalent to 2 times the fixed 

 part of rennet and i c.c. of the second serum corresponded 

 to 2.1 part of the rennet. The observed values in the 

 first series are mean values of three, and in the second of 

 two different series of measurements. 



NEUTRALISATION OF RENNET BY MEANS OF NORMAL HORSE-SERUM 



The circumstance that the neutralisation of the antibody 

 rom normal serum follows quite different laws than those 

 alid for the antirennet produced by immunisation, is a 

 ertain indication that these two antibodies are really 

 ifferent substances. This is also probable because the 

 ntirennet is much more easily destroyed by heat than the 

 ntibody from normal serum.* The occurrence of many 

 ntibodies in normal sera led Ehrlich to the supposition 



'This criterion gives alone no absolutely certain indication, for the thermo- 

 ihty of a dissolved substance may depend to a rather high degree on 

 e presence of other substances, as salts or proteids (^. pepton), in the 

 >lution. Cf. Biernacki: Zeitschr.f. Biologic, 28 (1891) 



