Fig. 1. — Antic()iri|il('niontiii y litiatiou of antigen in tlie presence of normal serum. 



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Fig. 2. — Antigenic titration in tlie presence of positi\e serum. 

 Plate VI. — AxTico.MPi.K.NtKXTAKY and Axtige.vic Titratiox ok Axtigex. 



