The question of smokes is more serious. It was the hope of the producers of irritant smokes that they would penetrate the gas-masks in sufficient amounts to cause sneezing and force their victims to remove their masks, thus exposing themselves to greater concentrations of smoke and to poisonous vapours liberated along with the smoke. This was the German view when they introduced the “Blue Cross” shell in July, 1917. Fortunately, by that time our defence against gas and smoke was extremely good, and we had foreseen the smoke menace and introduced, between April and June, 1917, a filter which effectively stopped it in the concentrations then met in the field. It is not, however, at all unlikely that concentrations of smoke will be produced in the future which will penetrate our present masks. If our anti-gas measures are sufficiently neglected the consequences may, of course, be very serious.
It would seem likely that the chemical weapons of the future will not be so very unlike those of the past. The main efforts of the soldier who uses them will be devoted, first, to blistering his enemy, secondly, to tiring him out by forcing him to wear a respirator continuously, which, of course, enormously hampers him for doing anything else.
In the Great War mustard gas and sensory irritant smokes were not used as the principal weapons of attack or defence, because the smokes would not incapacitate everyone in a given area, though they would make them keep their respirators on. Mustard gas, on the other hand, could make any area absolutely untenable by the defenders, but the vapour persisted for so many days that it could not be occupied by the attackers either. It was mainly used to produce casualties a few days or weeks before an attack on the units which would be defending, and to protect the flank of an offensive against counter-attack. Thus in April, 1918, Armentières, the original Northern limit of the German attack in Flanders, was so heavily shelled with “mustard” that the gutters in the streets were reported to be running with it. The Germans themselves received orders forbidding them to enter its ruins for a fortnight.
Nevertheless, mustard gas is so adequate a weapon that the attempt will almost certainly be made to use it not merely for making ground untenable for both sides, but for gaining it from the enemy. For this purpose the following methods suggest themselves. First, attempts might be made to protect troops completely from the effect of gas on their skins by encasing them in airtight overalls and gloves. These were used with a certain amount of success by machine-gunners in the Great War, but would hardly be practicable for attackers, who would, except perhaps in winter, die of heat-stroke if encased in such apparatus.
Air-tight tanks with adequate arrangements for filtering the incoming air are probably more hopeful, as mustard gas will not poison motors as it does men. (The motors would, of course, have their own air-supply, as it would hardly be practicable to filter air in the quantities needed by them.) To support the tanks and to tackle specially protected machine-gunners use will probably be made of immune infantry. One attack of gas-poisoning, whether by the lungs or skin, produces no immunity to a second attack—in fact, it generally increases the sensitivity of the victim. If a vapour is discovered against which immunity can be conferred, it will be the most effective weapon in history as long as its secret is kept. On the other hand, some people are naturally immune. The American Army authorities made a systematic examination of the susceptibility of large numbers of recruits. They found that there was a very resistant class, comprising 20% of the white men tried, but no less than 80% of the negroes. This as intelligible, as the symptoms of mustard gas, blistering, and sun-burn are very similar, and negroes are pretty well immune to sun-burn. It looks therefore as if, after a slight preliminary test, it should be possible to obtain coloured troops who would all be resistant to mustard gas blistering in concentrations harmful toward most white men. Enough resistant whites are available to officer them.
One sees, then, the possibility of warfare on somewhat the following lines:—
Heavy concentrations of artillery would keep an area say thirty miles in length and ten in depth continuously sprayed with mustard gas. After allowing, say, two days for the development of blisters, the gassing of the positions within two or three miles of the front line is discontinued, but a long-range bombardment, especially of roads, goes on. Suddenly, behind the usual barrage of high explosive shells appears a line of tanks supported by negroes in gas-masks. They meet with but little opposition in the area still reeking of gas, and occupy the hostile lines to a depth of two or three miles. A counter-attack, even if successful, involves concentration in an area under gas-bombardment and enormous casualties from blistering. The only satisfactory counter-attack would be from the air. In this way the side possessing a big superiority of mustard gas should be in a position to advance two or three miles a day.
This kind of tactics was impossible during the Great War for a very simple reason. There was not enough mustard gas. The Germans used a quite surprisingly complicated process for its manufacture. When we decided to follow their example, one of our chemists (a Cambridge man, I am glad to say) hit on a vastly cheaper and speedier method of manufacture. Unfortunately, our first supplies only arrived in the field in September, 1918. There is reason to think that the knowledge that we were at last about to develop gas and smoke warfare on a large scale had a good deal to do with the acceptance by the Germans of the armistice conditions.
The reason why we did not use mustard gas earlier is also simple and rather instructive.
In 1915 a British chemist proposed to a General who was concerned with such questions that the British should use dichlorethyl sulphide. “Does it kill?” asked the General. “No,” he was told, “but it will disable enormous numbers of the enemy temporarily.” “That is no good to us,” said the man of blood; “we want something that will kill.” It is interesting to find how completely the ideas of this worthy soldier as to the object of war coincided with those of the average intelligent child of five years old. I may remind you that Clausewitz held the view that the object of war was to impose one’s will upon the enemy. This idea would, however, appear to have been too abstract, too complicated, or too humanitarian for the British military mind. At any rate, it had its fill of killing. It was not, therefore, until the Germans had demonstrated upon the persons of some tens of thousands of British soldiers (we had 14,000 casualties, though with only 400 deaths, during the first three weeks of the mustard gas war) that there was something to be said for a weapon that was not primarily designed to kill, that we began to use it.