A decrease of the variance of a caloric test would increase the importance of the statement of this test. An important source of variance are the differences concerning the timecourse of the induced heat wave, determined by the different anatomic conditions in the petrous bone, particularly the pneumatisation. A constant temperature gradient is obtained by the irigation in a pessimum position with the head flexed 30 degrees to the front. This temperature gradient evokes immediately a constant maximum vestibular stimulus after having reflected the head 90 degrees to the back. Comparing this new method with the traditional irrigation, one can state an important reduction of variance. The dependence of the nystagumus response on caloric irrigation of the petrous bone demands a X-ray-examination according to the technique of Schüller before starting with the caloric examination. In case of differences between the right and left sides the described test would be necessary in our opinion.