(5) x" -q(x)y=0 of (2), cf. [5]. The purpose of this paper is an application of this result to the case of certain classical linear differential equations occurring in mathematical physics. For instance, there will be considered (? 1) the so-called toroidal functions which, in the main, are certain normalizations of the associated Legendre functions. The latter are not hypergeometric functions. Applications will, however, be given (? 2) to the hypergeometric differential eqjuation, and K:ummer's confluent case will also be considered -(? 3).