Anomaly in the tunneling $\mathbf{I(V)}$ characteristics of Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$

Tunneling measurements have been carried out on slightly overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ single crystals below and above the critical temperature by break-junctions and in-plane point-contacts. An anomaly was found in the tunneling $I(V)$ characteristics. Analysis of the data shows that the anomaly is caused by the superconducting condensate. In the extracted $I(V)$ characteristics of the condensate, the constant asymptotics points to the presence of one-dimensionality in Bi2212. The anomaly found here puts additional constraints on the final theory of high-$T_c$ superconductivity.