The Medical Department was exceedingly prompt and vigorous in the treatment of these cases, which probably accounted for the very low mortality. This is one of the most interesting cases of the delayed action that may occur in gassing from phosgene. Here the concentration was slight and there is no doubt its effectiveness was largely due to the severe exercise taken by the men during and after the gassing. It should be remarked in closing that while gas officers were not consulted in the planning of this attack, a general order was shortly thereafter issued requiring that gas officers be consulted whenever gas was to be used. CHAPTER VII LACHRYMATORS Without question the eyes are the most sensitive part of the body so far as chemical warfare is concerned. Lachrymators are substances which affect the eyes, causing involuntary weeping. These substances can produce an intolerable atmosphere in concentrations one thousand times as dilute as that required for the most effective lethal agent. The great military value of these gases has already been mentioned and will be discussed more fully later. There are a number of compounds which have some value as lachrymators, though a few are very much better than all the others. Practically all of them have no lethal properties in the concentrations in which they are efficient lachrymators, though we must not lose sight of the fact that many of them have a high lethal value if the concentration is of the order of the usual poison gas. The lachrymators are used alone when it is desired to neutralize a given territory or simply to harrass the enemy. At other times they are used with lethal gases to force the immediate or to prolong the wearing of the mask. A large number of the lachrymators contain bromine. In order to maintain the gas warfare requirements, it was early decided that the bromine supply would have to be considerably increased. The most favorable source of bromine is the subterranean basin found in the vicinity of Midland, Michigan. Because of the extensive experience of the Dow Chemical Co. in all matters pertaining to the production of bromine, they were given charge of the sinking of seventeen government wells, capable of producing 650,000 pounds of bromine per year. While the plant was not operated during the War, it was later operated to complete a contract for 500,000 pounds of bromine salts. They will be held as a future war asset of the United States. The principal lachrymators used during the War were: Bromoacetone, Bromomethylethylketone, Benzyl bromide, Ethyl iodoacetate, Bromobenzyl cyanide, Phenyl carbylamine chloride. Chloropicrin is something of a lachrymator, but it has greater value as a toxic gas. HALOGENATED KETONES