All this leads one to ask the question that has vexed historians since 1945: why didn't Hitler use chemical weapons against the Allies? After all, he had shown no qualms against using gas on Jewish men, women and children, so why not against enemy troops as well?

Until now, many believed his reluctance to use these weapons on Allied soldiers stemmed from his own bitter experiences of being gassed during World War I.

As a young soldier, on the night of October 13-14, 1918, near Ypres, Corporal Hitler was exposed to mustard gas released by the British that left him temporarily blind. It ended his war, and apparently left him with a strong desire never to see gas used again.