In the previous paper2 it was observed that the formation of a carbon-carbon bond or bridge between the two benzene nuclei in certain basic esters of diphenylacetic acid resulted in a marked increase in spasmolytic activity without increasing the toxicity. Thus 0- diethylaminoethyl fluorene-9-carboxylate which possessed the highest therapeutic index of the series, is approximately six times as effective as the corresponding ester of ...