534 



A CONTRIBUTION TO THK STUDY OF THE PRECIPITINS, 



Precipitates were obtained in each tube. The homologous 

 protein was thus not exhausted in any tube, and in spite of the 

 fact that only one-fifth of the amount originally present was 

 taken, it was still capable of eliciting from a second quantity of 

 antiserum precipitates not less abundant than those obtained in 

 the primary interactions. An apparent excei)tion is tube 4, in 

 which occurred a deposit much smaller than that primarily given. 

 But the smaller precipitate in this instance reinforces the argu- 

 ment, since it is in all probability attributable not to the 

 exhaustion of the homologous proteid but to the fact that the 

 amount of horse-serum (0-00005 gm.) originally present was just 

 insufficient to neutralise 001 gm. antiserum, and that the amount 



Precipitates 



in 



48 hours. 



0-3 mm. 



1 mm. 



none, 

 none. 



actually present in thesecondary reaction was 000001 gm. (already 

 once acted on), making the interacting quantities more nearly 

 equal to those in the primary tube 5. In tubes 4, 5, 6 and 7 

 uncombined precipitin (antiserum) coexisted with uncombined 

 homologous protein in the clear superfluid. 



