540 A CONTRIBUTION TO THE STUDY OF THE PRECIPITINS, 



of precipitate remains practically constant although the protein 

 increases from 14 gm. to 432 gm. A somewhat similar series is 

 recorded in Table x. In this series 3 c.c. antiserum were allowed 

 to interact with 70, 140, 280 and 560 mg. dried egg-white. After 

 24 hours the superfluids were removed; to the superfluid of the 

 first tube 70 nisf. dried egg-white were added, to the second tube 

 1 40 mg. dried egg-white were added, and the remaining tubes 

 were tested in the usual way. The precipitates were treated in 

 the manner above described and weighed. No pr(<cipitates 

 occurred in the secondary tubes 3 and 4. 



Table x. 



The superfluids fiom tubes 2B and IB were tested for the 

 presence of precipitin by the addition of more protein, but no 

 precipitates were obtained. In this series the weight of precipi- 

 tate obtained from 1 c.c. antiserum remains constant despite the 

 large increase in the quantity of protein. No stress can be laid 

 on the amount of precipitate in tube IB, since it is doubtful 

 whether the interaction in tube 1 was complete in 24 hours. 



As it appears that the precipitate from a given quantity of 

 antiserum is constant, provided there be sufficient protein to 

 neutralise the precipitin, a series of experiments in which the 

 amount of antiserum was varied may be considered. With these 

 experiments may be considered one in which a duplicate was 

 cai-ried out. The details of the experiments were varied to avoid 

 errors. The results are recorded in Table xi. 



