Chemical warfare

by Amos A. Fries; Clarence J. West

Medical

The Medical Section of the Chemical Warfare Service was composed of officers of the Medical Department of the Army attached to the Chemical Warfare Service. These were in addition to others who worked as an integral part of the Chemical Warfare Service, either at the laboratory or on the experimental field in carrying out experiments on animals to determine the effectiveness of the gases.

The Medical Section was important for the reason that it formed the connecting link between the Chemical Warfare Service and the Medical Department. Through this Section, the Medical Department was enabled to know the kinds of gases that would probably be handled, both by our own troops and by the enemy, and their probable physiological effects.

Colonel H. L. Gilchrist, Medical Department, was the head of this Section. It was through his efforts that the Medical Department realized in time the size of the problem that it had to encounter in caring for gas patients. Indeed, records of the war showed that out of 224,089 men, exclusive of Marines, admitted to the hospitals in France, 70,552 were suffering from gas alone. These men received a total of 266,112 wounds, of which 88,980, or 33.4 per cent, were gas. Thus ⅓ of all wounds received by men admitted to the hospital were gas. While the records show that the gas cases did not remain on the average in the hospitals quite as long as in the case of other classes of wounds, yet gas cases became one of the most important features of the Medical Department’s work in the field.

The Medical Section, through its intimate knowledge of what was going on in the Chemical Warfare Service as well as what was contemplated and being experimented with, was enabled to work out methods of handling all gas cases far in advance of what could have been done had there been no such section. One instance alone illustrates this fully. It became known fairly early that if a man who had been gassed with mustard gas could get a thorough cleansing and an entire change of clothing within an hour after exposure, the body burns could be eliminated or largely decreased in severity. This led to the development of degassing units. These consisted of 1,200 gallon tanks on five-ton trucks equipped with a heater. Accompanying this were sprinkling arrangements whereby a man could be given a shower bath, his nose, eyes and ears treated with bicarbonate of soda, and then be given an entire change of clothing. These proved a very great success, although they were not developed in time to be used extensively before the war closed.

There is an important side to the Medical Section during peace, that must be kept in mind. The final decision as to whether a gas should be manufactured on a large scale and used extensively on the field of battle depends upon its physiological and morale effect upon troops. In the case of the most powerful gases, the determination of the relative values of those gases so far as their effects on human beings is concerned is a very laborious and exacting job. Such gases have to be handled with extreme caution, necessitating many experiments over long periods of time in order to arrive at correct decisions.

CHAPTER V
CHLORINE

Chlorine is of interest in chemical warfare, not only because it was the first poison gas used by the Germans, but also because of its extensive use in the preparation of other war gases. The fact that, when Germany decided upon her gas program, her chemists selected chlorine as the first substance to be used, was the direct result of an analysis of the requirements of a poison gas.

To be of value for this purpose, a chemical must satisfy at least the following conditions:

(1) It must be highly toxic.

(2) It must be readily manufactured in large quantities.

(3) It must be readily compressible to a liquid and yet be more or less easily volatilized when the pressure is released.

(4) It should have a considerably higher density than that of air.

(5) It should be stable against moisture and other chemicals.

Considering the properties of chlorine in the light of these requirements, we find:

(1a) Chlorine is fairly toxic, though its lethal concentration (2.5 milligrams per liter of air) is very high when compared with some of the later gases developed. This figure is the concentration necessary to kill a dog after an exposure of thirty minutes. Its effects during the first gas attack showed that, with no protection, the gas was very effective.

(2a) Chlorine is very readily manufactured by the electrolysis of a salt (sodium chloride) solution. The operation is described below. In 100-pound cylinders, the commercial product sold before the War for 5 cents a pound. Therefore on a large scale, it can be manufactured at a very much smaller figure.

(3a) Chlorine is easily liquefied at the ordinary temperature by compression, a pressure of 16.5 atmospheres being required at 18° C. The liquid which is formed boils at -33.6° C. at ordinary atmospheric pressure, so that it readily vaporizes upon opening the valve of the containing cylinder. Such rapid evaporation inside would cause a considerable cooling of the cylinder, but this is overcome by running the outlet pipe to the bottom of the tank, so that evaporation takes place at the end of the outlet pipe.

(4a) Chlorine is 2.5 times as heavy as air, and therefore the gas is capable of traveling over a considerable distance before it dissipates into the atmosphere.

(5a) The only point in which chlorine does not seem to be an ideal gas, is in the fact that it is a reactive substance. This is best seen in the success of the primitive protection adopted by both the British and the French during the days immediately following the first gas attack.

At first, however, chlorine proved a very effective weapon. During the first six months of its use, its value was maintained by devising new methods of attack. When these were exhausted, phosgene was added ([see next chapter]). With the decline in importance of cloud gas attacks, and the development of more deadly gases, chlorine was all but discarded as a true war gas, but remained as a highly important ingredient in the manufacture of other toxic gases.