Even with the portable flammenwerfer, the most difficult thing to do is to get near enough the target to make the shoot effective. Another serious disadvantage is its very short duration. It is impossible to charge up again on the spot, and the result is that once the flame stops, the whole game is finished and the operators are at the mercy of the enemy. With these facts in mind it is easy to see how service in the flaming gun regiments is apparently a form of punishment. Men convicted of offenses in other regiments were transferred either for a time or permanently and were forced under threat of death in the most hazardous enterprises and to carry out the most dangerous work. Taken all in all the flame thrower was one of the greatest failures among the many promising devices tried out on a large scale in the war. CHAPTER XXI THE PHARMACOLOGY OF WAR GASES The pharmacology of war gases plays such an important part in chemical warfare that a brief discussion may well be given of the methods used in the testing of gases for toxicity and other pharmacological properties. War gases may be divided into two groups: persistent and non-persistent, each of which may include several classes: I. Lethal II. Lachrymatory III. Sternutatory IV. Special Each class necessitates special tests in order to determine whether or not it is suitable for further development. TOXICITY One of the first points which must be carefully determined in investigating a substance is its toxicity. It is important that this be determined for numerous reasons: 1. To determine what concentrations are dangerous in the field. 2. To ascertain how effective protective devices have to be to furnish sufficient protection against the gas. 3. To furnish a basis for accurate experimental work on the treatment of gassed cases. 4. To decide whether or not the material is worthy of further development in the laboratory or in the plant.