Preheat the oven to 350 degrees F. In a large bowl, combine the flour, sugar, cocoa, baking soda, baking powder, and salt. Mix well. Add the eggs, milk, oil, and vanilla. With an electric mixer, beat at medium speed for 2 minutes. Stir in the boiling water by hand. The batter will be thin. Pour into a greased bundt pan and bake for 40 minutes, or until a tester inserted in the cake comes out clean. Cool for 10 minutes in the pan on a wire rack, then remove from the pan and continue cooling on the rack. The cake will be very moist.