In the development of a plan of relief for major trigeminal neuralgia or tic douloureux, we have passed certain landmarks: First, section of the sensory root, as proposed by Spiller,1superseded resection of the gasserian ganglion in 1901. Secondly, the hazard of radical operations has been practically removed. In 1894, the mortality of resection of the gasserian ganglion was 22 per cent. In a series of 432 consecutive operations, the mortality in the Neurosurgical Clinic at the University Hospital has been only a fraction of 1 per cent. Thirdly, subtotal section of the sensory root replaced total section2in 1915; and finally, in 1919, it was proved2that the motor root need no longer be sacrificed. To be sure, other contributions have been made to the development of the technic, but these are the most important. In this contribution, I will write on only one phase of