"In the conflict which some still persist in calling the Great War, though it was great only in size, there was so much jumble and muddle and half-hearted experiment and so little visible military skill and ingenuity that a far-seeing and keen-thinking British colonel has declared that if the nations of the earth will only use their brains, the inevitable next war will show combat so transformed and reformed that the struggle of 1914 - 1918 will seem, by comparison, little more than a clash 'between barbaric hordes...'"
Click here to read about the new rules for warfare that were written as a result of the First World War - none of them pertain to the use of poison gas or submarines.