Francesco Guerra and Fabio Toninelli have developped a very powerful technique to study the high temperature behaviour of the Sherrington-Kirkpatrick mean field spin glass model. They show that this model is asymptoticaly comparable to a linear model. The key ingredient is a clever interpolation technique between the two different Hamiltonians describing the models. This paper contribution to the subject are the following: (1) The replica-symmetric solution holds for general spins, not just $\pm 1$ valued. (2) The proof does not involve cavitation but only first order differential calculus and Gaussian integration by parts.