Mix 1 package gelatin in 1 cup hot water and add 1/2 cup cold water. (Do this four times - once for each package.) Set aside.

Mix 2 packages Knox gelatin in 1/2 cup cold water. Add 2 cups hot milk. Add to this the mixture of sour cream, sugar and vanilla. Beat until creamy.

Starting with the gelatin layer and alternating with cream mixture, layer in clear 8 1/2 x 11 inch dish. Let each layer set for 1/2 hour before adding next layer.