286 THE NEW WORLD OF SCIENCE 



tect himself. Also the stress of struggle, work and excitement 

 on the battlefield requires a degree of perfection in heart action 

 and inervation that is rarely demanded in civil life. On the 

 other hand, the disabilities due to nervous and mental diseases 

 and to tuberculosis- an^ the venereal infections are an equal 

 handicap in the life of a civilian. Considering these circum- 

 stances it is probable that not over half of the 29.1 per cent, 

 rejected for military service were incapacitated in a civil sense. 



CASUALTIES FROM POISON GAS 



When looked at from one point of view poison gas is one 

 of the most humane weapons of warfare. Although 74,779 

 of the 274,217 battle casualties resulted from gas, the number 

 of deaths was very small, 1.87 per cent., as compared with 23.4 

 per cent, from shell and bullet wounds. These figures indi- 

 cate that a man suffering from poison gas has twelve times as 

 many chances for recovery as a man put out of action by other 

 weapons. 



In the early days of the war chlorin gas alone was used, be- 

 ing liberated in great clouds when the direction of the wind 

 was favorable, from steel cylinders of liquefied chlorin, and the 

 cloud was carried by the wind in the direction of the enemy. 

 Experience soon demonstrated that the poison gas was quite 

 difficult of control when used in this way, and the chlorin 

 cloud gas offensive was soon superseded by gas of many sorts 

 contained in explosive shells which could be placed exactly 

 where the enemy desired. Reference to other portions of this 

 work will give greater details of the methods of using gas. 

 Our interest at this moment lies in its medical aspect alone. 



The new gases were of many sorts, but the most important 

 was dichlor-ethyl-sulphid or mustard or yellow cross gas as 

 it was commonly called. The liquid gas vaporizes rather 

 slowly on the explosion of the shell, and in addition the fluid 

 itself is sprayed over all those in the immediate neighborhood 

 of the explosion. Its effects are not noticed at once, and are 

 really not much appreciated until about four hours after ex- 



