THE PRECIPITINS AND THEIR ANTIBODIES 



289 



lent to the quantity of calf-serum present. (This observa- 

 tion has really led to the determination of the equivalent 

 quantities of the two sera.) 



ACTION OF DIFFERENT QUANTITIES {A} OF HORSE-SERUM ON A GIVEN 

 QUANTITY (100) OF CALF-SERUM 



The calculated figures, which within the errors of ob- 

 servation agree with the observed values the magnitude 

 of the errors of observation may be judged by the differ- 

 ence of the two observations for ^4 = 75 are found in 

 the following manner : The quantity B of calf-serum (in 

 this case B = 100) may react with A equivalents of horse- 

 serum. Then a certain amount of precipitate, P lt is 

 formed, of which / parts are soluble in i c.c. and the 

 rest, P 1 p V= P, is packed in the capillary tube (y is 

 the volume of the mixture). Then there are remaining in 

 the solution A P l equivalents of horse-serum, and B P l 

 equivalents of calf-serum. But experience indicates that 

 a further addition of horse-serum dissolves the precipitate. 

 Let us suppose that there are formed Y equivalents of 



