  A simple analytic calculation is presented for the secular evolution of the
eccentricities in a hierarchical triple system such as the one containing the
millisecond pulsar PSR 1620-26 in M4. If the second companion of PSR 1620-26 is
of stellar mass ($m_2\ga0.1\,M_\odot$), an eccentricity as large as that
observed today for the inner binary ($e_1\simeq0.03$) could very well have been
induced by secular perturbations. In contrast, such a large eccentricity cannot
be induced by a second companion of planetary mass.
