The progress that has been made along these lines is indicated by the statement of Lord Northcliffe, who after a visit to the front declared that the annual death rate in the English army was 3 per cent of 1000 and that the average illness, including colds and influenza, was less than in London, despite the discomforts of the trenches. In the past disease has been as destructive as battles. Biology and pathology, to say nothing of surgery and therapeutics, have made such strides that disease has been virtually eliminated as a factor in warfare. War takes medical science into the field, where the control of large masses of men enables it to develop the highest efficiency. Even in normal peace conditions biological and pathological science has been accomplishing results not popularly understood. Individual cures by surgery and medicine appeal to personal interests, but these are negligible compared to the prevention of plagues like smallpox, typhus and tuberculosis. If such diseases had not been successfully combated by science three out of four of the present civilized population would not be in existence at all. The organized and intensive application and developments of science, of preventive medicine, constitute the strictly neutral work in this war by which all humanity will profit for all time to come. In passing it is interesting to note that the great power supplied by Niagara Falls is being utilized to produce some of the chemical marvels. One great industry there is making soda by the electrolytic process. That is, salt brine is pumped from the saline deposits in western New York and piped to the works. This is run into electric cells and through these a current of electricity is led. The salt, which is composed of chlorine and sodium, decomposes under the electric attack. The sodium goes to one pole and combines with water to form caustic soda, whereas the chlorine escapes at the other pole. Let us follow the chlorine, which is a yellowish-green gas, more than twice as heavy as air, and has found a new use as poison gas in the great war--for which all the world should be ashamed. It is collected and compressed to a liquid form and shipped in containers under pressure for use in chemical works and bleacheries and for the purification of drinking water. It has been found above all things effective in destroying noxious bacilli. A surprisingly small amount of the gas dissolved in the water is enough. In New York city the water has been chlorinated and no single case of typhoid fever has been traced to the supply. CHAPTER XXI. OUR NEIGHBORING ALLY. CANADA'S RECRUITING--RAISE 33,000 TROOPS IN TWO MONTHS--FIRST EXPEDITIONARY FORCE TO CROSS ATLANTIC--BRAVERY AT YPRES AND LENS--MEETING DIFFICULT PROBLEMS--QUEBEC AROUSED BY CONSCRIPTION.