number of occasions, and information indicates that since the last war German research in chemical warfare methods has been pursued unremittingly. 6. The following are considered the most likely methods of using gas against this country. (a) Aircraft spray using mustard. Over protected towns, for reasons of necessity, high spray is likely, To the best of our knowledge the Germans are not as far advanced in this technique as we are. Against troops on the march, in open country, particularly against civilian evacuees, low spray attacks are to be expected.