746 MEDICAL JURISPRUDENCE concentration is high, the vapour causes irritation of the respiratory passages and lungs, and produces a burning sensation in the throat and discomfort in the chest. In cases where the exposure is continued for a long time, there may be nausea, vomiting, tra- cheitis, bronchitis, and blistering of the skin. In rare cases there may be keratitis and corneal opacities. The effects are, as a rule, transitory, incapacitating persons for some hours only and are not dangerous to life. The treatment consists in washing the eyes with warm normal saline and removing the patient into fresh air. The respirator is a sufficient protector of the eyes and lungs against all tear gases of any concentration. IV. Sternutators or Nasal Irritants.—These are solid, organic compounds of arsenic, which are dispersed by heat or detonation in the form of very fine, participate clouds or smokes. The compounds which may be used during war are— 1. Diphenylchlorarsine (DA.), a colourless, crystalline solid. It is slightly soluble in water, but dissolves in phosgene and chloropicrin. 2. Diphenylamine-chlorarsine, or diphenylarsine-chlorarsine (D.M.), a yellow, al- most odourless, crystalline solid. It is not soluble in phosgene and tarnishes metals. 3. Diphenylcyanarsine (C.D.), a white, odourless, crystalline solid. The vapours of these substances, when inhaled, cause intense pain and irritation in the nose and _sinuses with excessive sneezing, malaise, headache, painful gums, salivation, nausea, vomiting, pain and tightness in the chest and temporary prostration- The effects are temporary, lasting for an hour or two, but are quite effective in destroying the morale of the enemy's troops* Water and food contaminated by these substances may give- rise to symptoms of arsenic poisoning. The treatment is fresh air. The nose should be irrigated with a 5 per cent solution of sodium carbonate. Gargles of the same solution may be used if there is irritation of the throat. A few whiffs of chloroform inhalation may be given if there is severe pain in the sinuses. V. Paralysants.—These are hydrocyanic acid and sulphuretted hydrogen,23 but they are not very useful in chemical warfare, as it is difficult to obtain them in their lethal concentrations during the time of war. 23. Vide pp. 703 and 717.