100 



ALAX ARTHUR BOYDEN. 



same relationship to beef whether an antibeef serum was titrated 

 with pig or whether an antipig serum was titrated with beef. 

 It would seem then that this principle of reciprocal relationships 

 could be used as a test of the truth of the values obtained in the 

 precipitin reaction. Table XIII. gives the values obtained in 

 these reciprocal titrations. The titrations which failed to exhibit 

 correspondence are marked with an asterisk. 



TABLE XIII. 



RECIPROCAL VALUES OF ANTISERA. 



reciprocal values have been obtained with rabbit 

 i nd of these twelve gave correspondence within the 



